diff --git a/.github/scripts/run-librispeech-pruned-transducer-stateless7-2022-11-11.sh b/.github/scripts/run-librispeech-pruned-transducer-stateless7-2022-11-11.sh
index 8e485d2e6..999841b80 100755
--- a/.github/scripts/run-librispeech-pruned-transducer-stateless7-2022-11-11.sh
+++ b/.github/scripts/run-librispeech-pruned-transducer-stateless7-2022-11-11.sh
@@ -30,6 +30,15 @@ ln -s pretrained.pt epoch-99.pt
 ls -lh *.pt
 popd
 
+log "Test exporting to ONNX format"
+./pruned_transducer_stateless7/export.py \
+  --exp-dir $repo/exp \
+  --use-averaged-model false \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --epoch 99 \
+  --avg 1 \
+  --onnx 1
+
 log "Export to torchscript model"
 ./pruned_transducer_stateless7/export.py \
   --exp-dir $repo/exp \
@@ -41,6 +50,27 @@ log "Export to torchscript model"
 
 ls -lh $repo/exp/*.pt
 
+log "Decode with ONNX models"
+
+./pruned_transducer_stateless7/onnx_check.py \
+  --jit-filename $repo/exp/cpu_jit.pt \
+  --onnx-encoder-filename $repo/exp/encoder.onnx \
+  --onnx-decoder-filename $repo/exp/decoder.onnx \
+  --onnx-joiner-filename $repo/exp/joiner.onnx \
+  --onnx-joiner-encoder-proj-filename $repo/exp/joiner_encoder_proj.onnx \
+  --onnx-joiner-decoder-proj-filename $repo/exp/joiner_decoder_proj.onnx
+
+./pruned_transducer_stateless7/onnx_pretrained.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --encoder-model-filename $repo/exp/encoder.onnx \
+  --decoder-model-filename $repo/exp/decoder.onnx \
+  --joiner-model-filename $repo/exp/joiner.onnx \
+  --joiner-encoder-proj-model-filename $repo/exp/joiner_encoder_proj.onnx \
+  --joiner-decoder-proj-model-filename $repo/exp/joiner_decoder_proj.onnx \
+  $repo/test_wavs/1089-134686-0001.wav \
+  $repo/test_wavs/1221-135766-0001.wav \
+  $repo/test_wavs/1221-135766-0002.wav
+
 log "Decode with models exported by torch.jit.script()"
 
 ./pruned_transducer_stateless7/jit_pretrained.py \
diff --git a/.github/workflows/run-librispeech-2022-11-11-stateless7.yml b/.github/workflows/run-librispeech-2022-11-11-stateless7.yml
index 365e2761a..7694e8bf5 100644
--- a/.github/workflows/run-librispeech-2022-11-11-stateless7.yml
+++ b/.github/workflows/run-librispeech-2022-11-11-stateless7.yml
@@ -39,7 +39,7 @@ concurrency:
 
 jobs:
   run_librispeech_2022_11_11_zipformer:
-    if: github.event.label.name == 'ready' || github.event.label.name == 'run-decode' || github.event_name == 'push' || github.event_name == 'schedule'
+    if: github.event.label.name == 'onnx' || github.event.label.name == 'ready' || github.event.label.name == 'run-decode' || github.event_name == 'push' || github.event_name == 'schedule'
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7/export.py b/egs/librispeech/ASR/pruned_transducer_stateless7/export.py
index 3e3160e7e..db8b5eb2b 100755
--- a/egs/librispeech/ASR/pruned_transducer_stateless7/export.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7/export.py
@@ -41,7 +41,31 @@ Check
 https://github.com/k2-fsa/sherpa
 for how to use the exported models outside of icefall.
 
-(2) Export `model.state_dict()`
+(2) Export to ONNX format
+
+./pruned_transducer_stateless7/export.py \
+  --exp-dir ./pruned_transducer_stateless7/exp \
+  --bpe-model data/lang_bpe_500/bpe.model \
+  --epoch 20 \
+  --avg 10 \
+  --onnx 1
+
+It will generate the following files in the given `exp_dir`.
+Check `onnx_check.py` for how to use them.
+
+    - encoder.onnx
+    - decoder.onnx
+    - joiner.onnx
+    - joiner_encoder_proj.onnx
+    - joiner_decoder_proj.onnx
+
+Please see ./onnx_pretrained.py for usage of the generated files
+
+Check
+https://github.com/k2-fsa/sherpa-onnx
+for how to use the exported models outside of icefall.
+
+(3) Export `model.state_dict()`
 
 ./pruned_transducer_stateless7/export.py \
   --exp-dir ./pruned_transducer_stateless7/exp \
@@ -172,6 +196,23 @@ def get_parser():
         """,
     )
 
+    parser.add_argument(
+        "--onnx",
+        type=str2bool,
+        default=False,
+        help="""If True, --jit is ignored and it exports the model
+        to onnx format. It will generate the following files:
+
+            - encoder.onnx
+            - decoder.onnx
+            - joiner.onnx
+            - joiner_encoder_proj.onnx
+            - joiner_decoder_proj.onnx
+
+        Refer to ./onnx_check.py and ./onnx_pretrained.py for how to use them.
+        """,
+    )
+
     parser.add_argument(
         "--context-size",
         type=int,
@@ -184,6 +225,204 @@ def get_parser():
     return parser
 
 
+def export_encoder_model_onnx(
+    encoder_model: nn.Module,
+    encoder_filename: str,
+    opset_version: int = 11,
+) -> None:
+    """Export the given encoder model to ONNX format.
+    The exported model has two inputs:
+
+        - x, a tensor of shape (N, T, C); dtype is torch.float32
+        - x_lens, a tensor of shape (N,); dtype is torch.int64
+
+    and it has two outputs:
+
+        - encoder_out, a tensor of shape (N, T, C)
+        - encoder_out_lens, a tensor of shape (N,)
+
+    Note: The warmup argument is fixed to 1.
+
+    Args:
+      encoder_model:
+        The input encoder model
+      encoder_filename:
+        The filename to save the exported ONNX model.
+      opset_version:
+        The opset version to use.
+    """
+    x = torch.zeros(1, 101, 80, dtype=torch.float32)
+    x_lens = torch.tensor([101], dtype=torch.int64)
+
+    #  encoder_model = torch.jit.script(encoder_model)
+    # It throws the following error for the above statement
+    #
+    # RuntimeError: Exporting the operator __is_ to ONNX opset version
+    # 11 is not supported. Please feel free to request support or
+    # submit a pull request on PyTorch GitHub.
+    #
+    # I cannot find which statement causes the above error.
+    # torch.onnx.export() will use torch.jit.trace() internally, which
+    # works well for the current reworked model
+    torch.onnx.export(
+        encoder_model,
+        (x, x_lens),
+        encoder_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["x", "x_lens"],
+        output_names=["encoder_out", "encoder_out_lens"],
+        dynamic_axes={
+            "x": {0: "N", 1: "T"},
+            "x_lens": {0: "N"},
+            "encoder_out": {0: "N", 1: "T"},
+            "encoder_out_lens": {0: "N"},
+        },
+    )
+    logging.info(f"Saved to {encoder_filename}")
+
+
+def export_decoder_model_onnx(
+    decoder_model: nn.Module,
+    decoder_filename: str,
+    opset_version: int = 11,
+) -> None:
+    """Export the decoder model to ONNX format.
+
+    The exported model has one input:
+
+        - y: a torch.int64 tensor of shape (N, decoder_model.context_size)
+
+    and has one output:
+
+        - decoder_out: a torch.float32 tensor of shape (N, 1, C)
+
+    Note: The argument need_pad is fixed to False.
+
+    Args:
+      decoder_model:
+        The decoder model to be exported.
+      decoder_filename:
+        Filename to save the exported ONNX model.
+      opset_version:
+        The opset version to use.
+    """
+    y = torch.zeros(10, decoder_model.context_size, dtype=torch.int64)
+    need_pad = False  # Always False, so we can use torch.jit.trace() here
+    # Note(fangjun): torch.jit.trace() is more efficient than torch.jit.script()
+    # in this case
+    torch.onnx.export(
+        decoder_model,
+        (y, need_pad),
+        decoder_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["y", "need_pad"],
+        output_names=["decoder_out"],
+        dynamic_axes={
+            "y": {0: "N"},
+            "decoder_out": {0: "N"},
+        },
+    )
+    logging.info(f"Saved to {decoder_filename}")
+
+
+def export_joiner_model_onnx(
+    joiner_model: nn.Module,
+    joiner_filename: str,
+    opset_version: int = 11,
+) -> None:
+    """Export the joiner model to ONNX format.
+    The exported joiner model has two inputs:
+
+        - projected_encoder_out: a tensor of shape (N, joiner_dim)
+        - projected_decoder_out: a tensor of shape (N, joiner_dim)
+
+    and produces one output:
+
+        - logit: a tensor of shape (N, vocab_size)
+
+    The exported encoder_proj model has one input:
+
+        - encoder_out: a tensor of shape (N, encoder_out_dim)
+
+    and produces one output:
+
+        - projected_encoder_out: a tensor of shape (N, joiner_dim)
+
+    The exported decoder_proj model has one input:
+
+        - decoder_out: a tensor of shape (N, decoder_out_dim)
+
+    and produces one output:
+
+        - projected_decoder_out: a tensor of shape (N, joiner_dim)
+    """
+    encoder_proj_filename = str(joiner_filename).replace(".onnx", "_encoder_proj.onnx")
+    decoder_proj_filename = str(joiner_filename).replace(".onnx", "_decoder_proj.onnx")
+
+    encoder_out_dim = joiner_model.encoder_proj.weight.shape[1]
+    decoder_out_dim = joiner_model.decoder_proj.weight.shape[1]
+    joiner_dim = joiner_model.decoder_proj.weight.shape[0]
+
+    projected_encoder_out = torch.rand(1, 1, 1, joiner_dim, dtype=torch.float32)
+    projected_decoder_out = torch.rand(1, 1, 1, joiner_dim, dtype=torch.float32)
+
+    project_input = False
+    # Note: It uses torch.jit.trace() internally
+    torch.onnx.export(
+        joiner_model,
+        (projected_encoder_out, projected_decoder_out, project_input),
+        joiner_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=[
+            "encoder_out",
+            "decoder_out",
+            "project_input",
+        ],
+        output_names=["logit"],
+        dynamic_axes={
+            "encoder_out": {0: "N"},
+            "decoder_out": {0: "N"},
+            "logit": {0: "N"},
+        },
+    )
+    logging.info(f"Saved to {joiner_filename}")
+
+    encoder_out = torch.rand(1, encoder_out_dim, dtype=torch.float32)
+    torch.onnx.export(
+        joiner_model.encoder_proj,
+        encoder_out,
+        encoder_proj_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["encoder_out"],
+        output_names=["projected_encoder_out"],
+        dynamic_axes={
+            "encoder_out": {0: "N"},
+            "projected_encoder_out": {0: "N"},
+        },
+    )
+    logging.info(f"Saved to {encoder_proj_filename}")
+
+    decoder_out = torch.rand(1, decoder_out_dim, dtype=torch.float32)
+    torch.onnx.export(
+        joiner_model.decoder_proj,
+        decoder_out,
+        decoder_proj_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["decoder_out"],
+        output_names=["projected_decoder_out"],
+        dynamic_axes={
+            "decoder_out": {0: "N"},
+            "projected_decoder_out": {0: "N"},
+        },
+    )
+    logging.info(f"Saved to {decoder_proj_filename}")
+
+
 @torch.no_grad()
 def main():
     args = get_parser().parse_args()
@@ -292,7 +531,31 @@ def main():
     model.to("cpu")
     model.eval()
 
-    if params.jit is True:
+    if params.onnx is True:
+        convert_scaled_to_non_scaled(model, inplace=True)
+        opset_version = 13
+        logging.info("Exporting to onnx format")
+        encoder_filename = params.exp_dir / "encoder.onnx"
+        export_encoder_model_onnx(
+            model.encoder,
+            encoder_filename,
+            opset_version=opset_version,
+        )
+
+        decoder_filename = params.exp_dir / "decoder.onnx"
+        export_decoder_model_onnx(
+            model.decoder,
+            decoder_filename,
+            opset_version=opset_version,
+        )
+
+        joiner_filename = params.exp_dir / "joiner.onnx"
+        export_joiner_model_onnx(
+            model.joiner,
+            joiner_filename,
+            opset_version=opset_version,
+        )
+    elif params.jit is True:
         convert_scaled_to_non_scaled(model, inplace=True)
         # We won't use the forward() method of the model in C++, so just ignore
         # it here.
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7/onnx_check.py b/egs/librispeech/ASR/pruned_transducer_stateless7/onnx_check.py
new file mode 100755
index 000000000..63acc0922
--- /dev/null
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7/onnx_check.py
@@ -0,0 +1,286 @@
+#!/usr/bin/env python3
+#
+# Copyright 2022 Xiaomi Corporation (Author: Fangjun Kuang)
+#
+# See ../../../../LICENSE for clarification regarding multiple authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+This script checks that exported onnx models produce the same output
+with the given torchscript model for the same input.
+"""
+
+import argparse
+import logging
+
+import onnxruntime as ort
+import torch
+
+from icefall import is_module_available
+
+if not is_module_available("onnxruntime"):
+    raise ValueError("Please 'pip install onnxruntime' first.")
+
+
+ort.set_default_logger_severity(3)
+
+
+def get_parser():
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter
+    )
+
+    parser.add_argument(
+        "--jit-filename",
+        required=True,
+        type=str,
+        help="Path to the torchscript model",
+    )
+
+    parser.add_argument(
+        "--onnx-encoder-filename",
+        required=True,
+        type=str,
+        help="Path to the onnx encoder model",
+    )
+
+    parser.add_argument(
+        "--onnx-decoder-filename",
+        required=True,
+        type=str,
+        help="Path to the onnx decoder model",
+    )
+
+    parser.add_argument(
+        "--onnx-joiner-filename",
+        required=True,
+        type=str,
+        help="Path to the onnx joiner model",
+    )
+
+    parser.add_argument(
+        "--onnx-joiner-encoder-proj-filename",
+        required=True,
+        type=str,
+        help="Path to the onnx joiner encoder projection model",
+    )
+
+    parser.add_argument(
+        "--onnx-joiner-decoder-proj-filename",
+        required=True,
+        type=str,
+        help="Path to the onnx joiner decoder projection model",
+    )
+
+    return parser
+
+
+def test_encoder(
+    model: torch.jit.ScriptModule,
+    encoder_session: ort.InferenceSession,
+):
+    inputs = encoder_session.get_inputs()
+    outputs = encoder_session.get_outputs()
+    input_names = [n.name for n in inputs]
+    output_names = [n.name for n in outputs]
+
+    assert inputs[0].shape == ["N", "T", 80]
+    assert inputs[1].shape == ["N"]
+
+    for N in [1, 5]:
+        for T in [12, 50]:
+            print("N, T", N, T)
+            x = torch.rand(N, T, 80, dtype=torch.float32)
+            x_lens = torch.randint(low=10, high=T + 1, size=(N,))
+            x_lens[0] = T
+
+            encoder_inputs = {
+                input_names[0]: x.numpy(),
+                input_names[1]: x_lens.numpy(),
+            }
+
+            torch_encoder_out, torch_encoder_out_lens = model.encoder(x, x_lens)
+
+            encoder_out, encoder_out_lens = encoder_session.run(
+                output_names,
+                encoder_inputs,
+            )
+
+            torch_encoder_out, torch_encoder_out_lens = model.encoder(x, x_lens)
+
+            encoder_out = torch.from_numpy(encoder_out)
+            assert torch.allclose(encoder_out, torch_encoder_out, atol=1e-05), (
+                (encoder_out - torch_encoder_out).abs().max(),
+                encoder_out.shape,
+                torch_encoder_out.shape,
+            )
+
+
+def test_decoder(
+    model: torch.jit.ScriptModule,
+    decoder_session: ort.InferenceSession,
+):
+    inputs = decoder_session.get_inputs()
+    outputs = decoder_session.get_outputs()
+    input_names = [n.name for n in inputs]
+    output_names = [n.name for n in outputs]
+
+    assert inputs[0].shape == ["N", 2]
+    for N in [1, 5, 10]:
+        y = torch.randint(low=1, high=500, size=(10, 2))
+
+        decoder_inputs = {input_names[0]: y.numpy()}
+        decoder_out = decoder_session.run(
+            output_names,
+            decoder_inputs,
+        )[0]
+        decoder_out = torch.from_numpy(decoder_out)
+
+        torch_decoder_out = model.decoder(y, need_pad=False)
+        assert torch.allclose(decoder_out, torch_decoder_out, atol=1e-5), (
+            (decoder_out - torch_decoder_out).abs().max()
+        )
+
+
+def test_joiner(
+    model: torch.jit.ScriptModule,
+    joiner_session: ort.InferenceSession,
+    joiner_encoder_proj_session: ort.InferenceSession,
+    joiner_decoder_proj_session: ort.InferenceSession,
+):
+    joiner_inputs = joiner_session.get_inputs()
+    joiner_outputs = joiner_session.get_outputs()
+    joiner_input_names = [n.name for n in joiner_inputs]
+    joiner_output_names = [n.name for n in joiner_outputs]
+
+    assert joiner_inputs[0].shape == ["N", 1, 1, 512]
+    assert joiner_inputs[1].shape == ["N", 1, 1, 512]
+
+    joiner_encoder_proj_inputs = joiner_encoder_proj_session.get_inputs()
+    encoder_proj_input_name = joiner_encoder_proj_inputs[0].name
+
+    assert joiner_encoder_proj_inputs[0].shape == ["N", 384]
+
+    joiner_encoder_proj_outputs = joiner_encoder_proj_session.get_outputs()
+    encoder_proj_output_name = joiner_encoder_proj_outputs[0].name
+
+    joiner_decoder_proj_inputs = joiner_decoder_proj_session.get_inputs()
+    decoder_proj_input_name = joiner_decoder_proj_inputs[0].name
+
+    assert joiner_decoder_proj_inputs[0].shape == ["N", 512]
+
+    joiner_decoder_proj_outputs = joiner_decoder_proj_session.get_outputs()
+    decoder_proj_output_name = joiner_decoder_proj_outputs[0].name
+
+    for N in [1, 5, 10]:
+        encoder_out = torch.rand(N, 384)
+        decoder_out = torch.rand(N, 512)
+
+        projected_encoder_out = torch.rand(N, 1, 1, 512)
+        projected_decoder_out = torch.rand(N, 1, 1, 512)
+
+        joiner_inputs = {
+            joiner_input_names[0]: projected_encoder_out.numpy(),
+            joiner_input_names[1]: projected_decoder_out.numpy(),
+        }
+        joiner_out = joiner_session.run(joiner_output_names, joiner_inputs)[0]
+        joiner_out = torch.from_numpy(joiner_out)
+
+        torch_joiner_out = model.joiner(
+            projected_encoder_out,
+            projected_decoder_out,
+            project_input=False,
+        )
+        assert torch.allclose(joiner_out, torch_joiner_out, atol=1e-5), (
+            (joiner_out - torch_joiner_out).abs().max()
+        )
+
+        # Now test encoder_proj
+        joiner_encoder_proj_inputs = {encoder_proj_input_name: encoder_out.numpy()}
+        joiner_encoder_proj_out = joiner_encoder_proj_session.run(
+            [encoder_proj_output_name], joiner_encoder_proj_inputs
+        )[0]
+        joiner_encoder_proj_out = torch.from_numpy(joiner_encoder_proj_out)
+
+        torch_joiner_encoder_proj_out = model.joiner.encoder_proj(encoder_out)
+        assert torch.allclose(
+            joiner_encoder_proj_out, torch_joiner_encoder_proj_out, atol=1e-5
+        ), ((joiner_encoder_proj_out - torch_joiner_encoder_proj_out).abs().max())
+
+        # Now test decoder_proj
+        joiner_decoder_proj_inputs = {decoder_proj_input_name: decoder_out.numpy()}
+        joiner_decoder_proj_out = joiner_decoder_proj_session.run(
+            [decoder_proj_output_name], joiner_decoder_proj_inputs
+        )[0]
+        joiner_decoder_proj_out = torch.from_numpy(joiner_decoder_proj_out)
+
+        torch_joiner_decoder_proj_out = model.joiner.decoder_proj(decoder_out)
+        assert torch.allclose(
+            joiner_decoder_proj_out, torch_joiner_decoder_proj_out, atol=1e-5
+        ), ((joiner_decoder_proj_out - torch_joiner_decoder_proj_out).abs().max())
+
+
+@torch.no_grad()
+def main():
+    args = get_parser().parse_args()
+    logging.info(vars(args))
+
+    model = torch.jit.load(args.jit_filename)
+
+    options = ort.SessionOptions()
+    options.inter_op_num_threads = 1
+    options.intra_op_num_threads = 1
+
+    logging.info("Test encoder")
+    encoder_session = ort.InferenceSession(
+        args.onnx_encoder_filename,
+        sess_options=options,
+    )
+    test_encoder(model, encoder_session)
+
+    logging.info("Test decoder")
+    decoder_session = ort.InferenceSession(
+        args.onnx_decoder_filename,
+        sess_options=options,
+    )
+    test_decoder(model, decoder_session)
+
+    logging.info("Test joiner")
+    joiner_session = ort.InferenceSession(
+        args.onnx_joiner_filename,
+        sess_options=options,
+    )
+    joiner_encoder_proj_session = ort.InferenceSession(
+        args.onnx_joiner_encoder_proj_filename,
+        sess_options=options,
+    )
+    joiner_decoder_proj_session = ort.InferenceSession(
+        args.onnx_joiner_decoder_proj_filename,
+        sess_options=options,
+    )
+    test_joiner(
+        model,
+        joiner_session,
+        joiner_encoder_proj_session,
+        joiner_decoder_proj_session,
+    )
+    logging.info("Finished checking ONNX models")
+
+
+if __name__ == "__main__":
+    torch.manual_seed(20220727)
+    formatter = "%(asctime)s %(levelname)s [%(filename)s:%(lineno)d] %(message)s"
+
+    logging.basicConfig(format=formatter, level=logging.INFO)
+    main()
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7/onnx_pretrained.py b/egs/librispeech/ASR/pruned_transducer_stateless7/onnx_pretrained.py
new file mode 100755
index 000000000..3a06ee293
--- /dev/null
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7/onnx_pretrained.py
@@ -0,0 +1,388 @@
+#!/usr/bin/env python3
+# Copyright      2022  Xiaomi Corp.        (authors: Fangjun Kuang)
+#
+# See ../../../../LICENSE for clarification regarding multiple authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+This script loads ONNX models and uses them to decode waves.
+You can use the following command to get the exported models:
+
+./pruned_transducer_stateless7/export.py \
+  --exp-dir ./pruned_transducer_stateless7/exp \
+  --bpe-model data/lang_bpe_500/bpe.model \
+  --epoch 20 \
+  --avg 10 \
+  --onnx 1
+
+Usage of this script:
+
+./pruned_transducer_stateless7/onnx_pretrained.py \
+  --encoder-model-filename ./pruned_transducer_stateless7/exp/encoder.onnx \
+  --decoder-model-filename ./pruned_transducer_stateless7/exp/decoder.onnx \
+  --joiner-model-filename ./pruned_transducer_stateless7/exp/joiner.onnx \
+  --joiner-encoder-proj-model-filename ./pruned_transducer_stateless7/exp/joiner_encoder_proj.onnx \
+  --joiner-decoder-proj-model-filename ./pruned_transducer_stateless7/exp/joiner_decoder_proj.onnx \
+  --bpe-model ./data/lang_bpe_500/bpe.model \
+  /path/to/foo.wav \
+  /path/to/bar.wav
+"""
+
+import argparse
+import logging
+import math
+from typing import List
+
+import kaldifeat
+import numpy as np
+import onnxruntime as ort
+import sentencepiece as spm
+import torch
+import torchaudio
+from torch.nn.utils.rnn import pad_sequence
+
+
+def get_parser():
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter
+    )
+
+    parser.add_argument(
+        "--encoder-model-filename",
+        type=str,
+        required=True,
+        help="Path to the encoder onnx model. ",
+    )
+
+    parser.add_argument(
+        "--decoder-model-filename",
+        type=str,
+        required=True,
+        help="Path to the decoder onnx model. ",
+    )
+
+    parser.add_argument(
+        "--joiner-model-filename",
+        type=str,
+        required=True,
+        help="Path to the joiner onnx model. ",
+    )
+
+    parser.add_argument(
+        "--joiner-encoder-proj-model-filename",
+        type=str,
+        required=True,
+        help="Path to the joiner encoder_proj onnx model. ",
+    )
+
+    parser.add_argument(
+        "--joiner-decoder-proj-model-filename",
+        type=str,
+        required=True,
+        help="Path to the joiner decoder_proj onnx model. ",
+    )
+
+    parser.add_argument(
+        "--bpe-model",
+        type=str,
+        help="""Path to bpe.model.""",
+    )
+
+    parser.add_argument(
+        "sound_files",
+        type=str,
+        nargs="+",
+        help="The input sound file(s) to transcribe. "
+        "Supported formats are those supported by torchaudio.load(). "
+        "For example, wav and flac are supported. "
+        "The sample rate has to be 16kHz.",
+    )
+
+    parser.add_argument(
+        "--sample-rate",
+        type=int,
+        default=16000,
+        help="The sample rate of the input sound file",
+    )
+
+    parser.add_argument(
+        "--context-size",
+        type=int,
+        default=2,
+        help="Context size of the decoder model",
+    )
+
+    return parser
+
+
+def read_sound_files(
+    filenames: List[str], expected_sample_rate: float
+) -> List[torch.Tensor]:
+    """Read a list of sound files into a list 1-D float32 torch tensors.
+    Args:
+      filenames:
+        A list of sound filenames.
+      expected_sample_rate:
+        The expected sample rate of the sound files.
+    Returns:
+      Return a list of 1-D float32 torch tensors.
+    """
+    ans = []
+    for f in filenames:
+        wave, sample_rate = torchaudio.load(f)
+        assert (
+            sample_rate == expected_sample_rate
+        ), f"expected sample rate: {expected_sample_rate}. Given: {sample_rate}"
+        # We use only the first channel
+        ans.append(wave[0])
+    return ans
+
+
+def greedy_search(
+    decoder: ort.InferenceSession,
+    joiner: ort.InferenceSession,
+    joiner_encoder_proj: ort.InferenceSession,
+    joiner_decoder_proj: ort.InferenceSession,
+    encoder_out: np.ndarray,
+    encoder_out_lens: np.ndarray,
+    context_size: int,
+) -> List[List[int]]:
+    """Greedy search in batch mode. It hardcodes --max-sym-per-frame=1.
+    Args:
+      decoder:
+        The decoder model.
+      joiner:
+        The joiner model.
+      joiner_encoder_proj:
+        The joiner encoder projection model.
+      joiner_decoder_proj:
+        The joiner decoder projection model.
+      encoder_out:
+        A 3-D tensor of shape (N, T, C)
+      encoder_out_lens:
+        A 1-D tensor of shape (N,).
+      context_size:
+        The context size of the decoder model.
+    Returns:
+      Return the decoded results for each utterance.
+    """
+    encoder_out = torch.from_numpy(encoder_out)
+    encoder_out_lens = torch.from_numpy(encoder_out_lens)
+    assert encoder_out.ndim == 3
+    assert encoder_out.size(0) >= 1, encoder_out.size(0)
+
+    packed_encoder_out = torch.nn.utils.rnn.pack_padded_sequence(
+        input=encoder_out,
+        lengths=encoder_out_lens.cpu(),
+        batch_first=True,
+        enforce_sorted=False,
+    )
+
+    projected_encoder_out = joiner_encoder_proj.run(
+        [joiner_encoder_proj.get_outputs()[0].name],
+        {joiner_encoder_proj.get_inputs()[0].name: packed_encoder_out.data.numpy()},
+    )[0]
+
+    blank_id = 0  # hard-code to 0
+
+    batch_size_list = packed_encoder_out.batch_sizes.tolist()
+    N = encoder_out.size(0)
+
+    assert torch.all(encoder_out_lens > 0), encoder_out_lens
+    assert N == batch_size_list[0], (N, batch_size_list)
+
+    hyps = [[blank_id] * context_size for _ in range(N)]
+
+    decoder_input_nodes = decoder.get_inputs()
+    decoder_output_nodes = decoder.get_outputs()
+
+    joiner_input_nodes = joiner.get_inputs()
+    joiner_output_nodes = joiner.get_outputs()
+
+    decoder_input = torch.tensor(
+        hyps,
+        dtype=torch.int64,
+    )  # (N, context_size)
+
+    decoder_out = decoder.run(
+        [decoder_output_nodes[0].name],
+        {
+            decoder_input_nodes[0].name: decoder_input.numpy(),
+        },
+    )[0].squeeze(1)
+    projected_decoder_out = joiner_decoder_proj.run(
+        [joiner_decoder_proj.get_outputs()[0].name],
+        {joiner_decoder_proj.get_inputs()[0].name: decoder_out},
+    )[0]
+
+    projected_decoder_out = torch.from_numpy(projected_decoder_out)
+
+    offset = 0
+    for batch_size in batch_size_list:
+        start = offset
+        end = offset + batch_size
+        current_encoder_out = projected_encoder_out[start:end]
+        # current_encoder_out's shape: (batch_size, encoder_out_dim)
+        offset = end
+
+        projected_decoder_out = projected_decoder_out[:batch_size]
+
+        logits = joiner.run(
+            [joiner_output_nodes[0].name],
+            {
+                joiner_input_nodes[0].name: np.expand_dims(
+                    np.expand_dims(current_encoder_out, axis=1), axis=1
+                ),
+                joiner_input_nodes[1]
+                .name: projected_decoder_out.unsqueeze(1)
+                .unsqueeze(1)
+                .numpy(),
+            },
+        )[0]
+        logits = torch.from_numpy(logits).squeeze(1).squeeze(1)
+        # logits'shape (batch_size, vocab_size)
+
+        assert logits.ndim == 2, logits.shape
+        y = logits.argmax(dim=1).tolist()
+        emitted = False
+        for i, v in enumerate(y):
+            if v != blank_id:
+                hyps[i].append(v)
+                emitted = True
+        if emitted:
+            # update decoder output
+            decoder_input = [h[-context_size:] for h in hyps[:batch_size]]
+            decoder_input = torch.tensor(
+                decoder_input,
+                dtype=torch.int64,
+            )
+            decoder_out = decoder.run(
+                [decoder_output_nodes[0].name],
+                {
+                    decoder_input_nodes[0].name: decoder_input.numpy(),
+                },
+            )[0].squeeze(1)
+            projected_decoder_out = joiner_decoder_proj.run(
+                [joiner_decoder_proj.get_outputs()[0].name],
+                {joiner_decoder_proj.get_inputs()[0].name: decoder_out},
+            )[0]
+            projected_decoder_out = torch.from_numpy(projected_decoder_out)
+
+    sorted_ans = [h[context_size:] for h in hyps]
+    ans = []
+    unsorted_indices = packed_encoder_out.unsorted_indices.tolist()
+    for i in range(N):
+        ans.append(sorted_ans[unsorted_indices[i]])
+
+    return ans
+
+
+@torch.no_grad()
+def main():
+    parser = get_parser()
+    args = parser.parse_args()
+    logging.info(vars(args))
+
+    session_opts = ort.SessionOptions()
+    session_opts.inter_op_num_threads = 1
+    session_opts.intra_op_num_threads = 1
+
+    encoder = ort.InferenceSession(
+        args.encoder_model_filename,
+        sess_options=session_opts,
+    )
+
+    decoder = ort.InferenceSession(
+        args.decoder_model_filename,
+        sess_options=session_opts,
+    )
+
+    joiner = ort.InferenceSession(
+        args.joiner_model_filename,
+        sess_options=session_opts,
+    )
+
+    joiner_encoder_proj = ort.InferenceSession(
+        args.joiner_encoder_proj_model_filename,
+        sess_options=session_opts,
+    )
+
+    joiner_decoder_proj = ort.InferenceSession(
+        args.joiner_decoder_proj_model_filename,
+        sess_options=session_opts,
+    )
+
+    sp = spm.SentencePieceProcessor()
+    sp.load(args.bpe_model)
+
+    logging.info("Constructing Fbank computer")
+    opts = kaldifeat.FbankOptions()
+    opts.device = "cpu"
+    opts.frame_opts.dither = 0
+    opts.frame_opts.snip_edges = False
+    opts.frame_opts.samp_freq = args.sample_rate
+    opts.mel_opts.num_bins = 80
+
+    fbank = kaldifeat.Fbank(opts)
+
+    logging.info(f"Reading sound files: {args.sound_files}")
+    waves = read_sound_files(
+        filenames=args.sound_files,
+        expected_sample_rate=args.sample_rate,
+    )
+
+    logging.info("Decoding started")
+    features = fbank(waves)
+    feature_lengths = [f.size(0) for f in features]
+
+    features = pad_sequence(
+        features,
+        batch_first=True,
+        padding_value=math.log(1e-10),
+    )
+
+    feature_lengths = torch.tensor(feature_lengths, dtype=torch.int64)
+
+    encoder_input_nodes = encoder.get_inputs()
+    encoder_out_nodes = encoder.get_outputs()
+    encoder_out, encoder_out_lens = encoder.run(
+        [encoder_out_nodes[0].name, encoder_out_nodes[1].name],
+        {
+            encoder_input_nodes[0].name: features.numpy(),
+            encoder_input_nodes[1].name: feature_lengths.numpy(),
+        },
+    )
+
+    hyps = greedy_search(
+        decoder=decoder,
+        joiner=joiner,
+        joiner_encoder_proj=joiner_encoder_proj,
+        joiner_decoder_proj=joiner_decoder_proj,
+        encoder_out=encoder_out,
+        encoder_out_lens=encoder_out_lens,
+        context_size=args.context_size,
+    )
+    s = "\n"
+    for filename, hyp in zip(args.sound_files, hyps):
+        words = sp.decode(hyp)
+        s += f"{filename}:\n{words}\n\n"
+    logging.info(s)
+
+    logging.info("Decoding Done")
+
+
+if __name__ == "__main__":
+    formatter = "%(asctime)s %(levelname)s [%(filename)s:%(lineno)d] %(message)s"
+
+    logging.basicConfig(format=formatter, level=logging.INFO)
+    main()
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7/scaling.py b/egs/librispeech/ASR/pruned_transducer_stateless7/scaling.py
index 1cbde6db0..156b91f09 100644
--- a/egs/librispeech/ASR/pruned_transducer_stateless7/scaling.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7/scaling.py
@@ -261,7 +261,7 @@ class RandomGrad(torch.nn.Module):
         self.min_abs = min_abs
 
     def forward(self, x: Tensor):
-        if torch.jit.is_scripting() or not self.training:
+        if torch.jit.is_scripting() or not self.training or torch.jit.is_tracing():
             return x
         else:
             return RandomGradFunction.apply(x, self.min_abs)
@@ -530,7 +530,7 @@ class ActivationBalancer(torch.nn.Module):
         self.register_buffer("count", torch.tensor(0, dtype=torch.int64))
 
     def forward(self, x: Tensor) -> Tensor:
-        if torch.jit.is_scripting() or not x.requires_grad:
+        if torch.jit.is_scripting() or not x.requires_grad or torch.jit.is_tracing():
             return _no_op(x)
 
         count = self.cpu_count
@@ -790,7 +790,7 @@ def with_loss(x, y):
 
 
 def _no_op(x: Tensor) -> Tensor:
-    if torch.jit.is_scripting():
+    if torch.jit.is_scripting() or torch.jit.is_tracing():
         return x
     else:
         # a no-op function that will have a node in the autograd graph,
@@ -862,6 +862,7 @@ class MaxEig(torch.nn.Module):
             torch.jit.is_scripting()
             or self.max_var_per_eig <= 0
             or random.random() > self.cur_prob
+            or torch.jit.is_tracing()
         ):
             return _no_op(x)
 
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7/test_onnx.py b/egs/librispeech/ASR/pruned_transducer_stateless7/test_onnx.py
new file mode 100644
index 000000000..2440d267c
--- /dev/null
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7/test_onnx.py
@@ -0,0 +1,374 @@
+#!/usr/bin/env python3
+# Copyright    2022  Xiaomi Corp.        (authors: Fangjun Kuang)
+#
+# See ../../../../LICENSE for clarification regarding multiple authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+"""
+This file is to test that models can be exported to onnx.
+"""
+import os
+
+from icefall import is_module_available
+
+if not is_module_available("onnxruntime"):
+    raise ValueError("Please 'pip install onnxruntime' first.")
+
+import onnxruntime as ort
+import torch
+from scaling_converter import convert_scaled_to_non_scaled
+from zipformer import (
+    Conv2dSubsampling,
+    RelPositionalEncoding,
+    Zipformer,
+    ZipformerEncoder,
+    ZipformerEncoderLayer,
+)
+
+ort.set_default_logger_severity(3)
+
+
+def test_conv2d_subsampling():
+    filename = "conv2d_subsampling.onnx"
+    opset_version = 13
+    N = 30
+    T = 50
+    num_features = 80
+    d_model = 512
+    x = torch.rand(N, T, num_features)
+
+    encoder_embed = Conv2dSubsampling(num_features, d_model)
+    encoder_embed.eval()
+    encoder_embed = convert_scaled_to_non_scaled(encoder_embed, inplace=True)
+
+    torch.onnx.export(
+        encoder_embed,
+        x,
+        filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["x"],
+        output_names=["y"],
+        dynamic_axes={
+            "x": {0: "N", 1: "T"},
+            "y": {0: "N", 1: "T"},
+        },
+    )
+
+    options = ort.SessionOptions()
+    options.inter_op_num_threads = 1
+    options.intra_op_num_threads = 1
+
+    session = ort.InferenceSession(
+        filename,
+        sess_options=options,
+    )
+
+    input_nodes = session.get_inputs()
+    assert input_nodes[0].name == "x"
+    assert input_nodes[0].shape == ["N", "T", num_features]
+
+    inputs = {input_nodes[0].name: x.numpy()}
+
+    onnx_y = session.run(["y"], inputs)[0]
+
+    onnx_y = torch.from_numpy(onnx_y)
+    torch_y = encoder_embed(x)
+    assert torch.allclose(onnx_y, torch_y, atol=1e-05), (onnx_y - torch_y).abs().max()
+
+    os.remove(filename)
+
+
+def test_rel_pos():
+    filename = "rel_pos.onnx"
+
+    opset_version = 13
+    N = 30
+    T = 50
+    num_features = 80
+    d_model = 512
+    x = torch.rand(N, T, num_features)
+
+    encoder_pos = RelPositionalEncoding(d_model, dropout_rate=0.1)
+    encoder_pos.eval()
+    encoder_pos = convert_scaled_to_non_scaled(encoder_pos, inplace=True)
+
+    x = x.permute(1, 0, 2)
+
+    torch.onnx.export(
+        encoder_pos,
+        x,
+        filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["x"],
+        output_names=["pos_emb"],
+        dynamic_axes={
+            "x": {0: "N", 1: "T"},
+            "pos_emb": {0: "N", 1: "T"},
+        },
+    )
+
+    options = ort.SessionOptions()
+    options.inter_op_num_threads = 1
+    options.intra_op_num_threads = 1
+
+    session = ort.InferenceSession(
+        filename,
+        sess_options=options,
+    )
+
+    input_nodes = session.get_inputs()
+    assert input_nodes[0].name == "x"
+    assert input_nodes[0].shape == ["N", "T", num_features]
+
+    inputs = {input_nodes[0].name: x.numpy()}
+    onnx_pos_emb = session.run(["pos_emb"], inputs)
+    onnx_pos_emb = torch.from_numpy(onnx_pos_emb[0])
+
+    torch_pos_emb = encoder_pos(x)
+    assert torch.allclose(onnx_pos_emb, torch_pos_emb, atol=1e-05), (
+        (onnx_pos_emb - torch_pos_emb).abs().max()
+    )
+    print(onnx_pos_emb.abs().sum(), torch_pos_emb.abs().sum())
+
+    os.remove(filename)
+
+
+def test_zipformer_encoder_layer():
+    filename = "zipformer_encoder_layer.onnx"
+    opset_version = 13
+    N = 30
+    T = 50
+
+    d_model = 384
+    attention_dim = 192
+    nhead = 8
+    feedforward_dim = 1024
+    dropout = 0.1
+    cnn_module_kernel = 31
+    pos_dim = 4
+
+    x = torch.rand(N, T, d_model)
+
+    encoder_pos = RelPositionalEncoding(d_model, dropout)
+    encoder_pos.eval()
+    encoder_pos = convert_scaled_to_non_scaled(encoder_pos, inplace=True)
+
+    x = x.permute(1, 0, 2)
+    pos_emb = encoder_pos(x)
+
+    encoder_layer = ZipformerEncoderLayer(
+        d_model,
+        attention_dim,
+        nhead,
+        feedforward_dim,
+        dropout,
+        cnn_module_kernel,
+        pos_dim,
+    )
+    encoder_layer.eval()
+    encoder_layer = convert_scaled_to_non_scaled(encoder_layer, inplace=True)
+
+    torch.onnx.export(
+        encoder_layer,
+        (x, pos_emb),
+        filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["x", "pos_emb"],
+        output_names=["y"],
+        dynamic_axes={
+            "x": {0: "T", 1: "N"},
+            "pos_emb": {0: "N", 1: "T"},
+            "y": {0: "T", 1: "N"},
+        },
+    )
+
+    options = ort.SessionOptions()
+    options.inter_op_num_threads = 1
+    options.intra_op_num_threads = 1
+
+    session = ort.InferenceSession(
+        filename,
+        sess_options=options,
+    )
+
+    input_nodes = session.get_inputs()
+    inputs = {
+        input_nodes[0].name: x.numpy(),
+        input_nodes[1].name: pos_emb.numpy(),
+    }
+    onnx_y = session.run(["y"], inputs)[0]
+    onnx_y = torch.from_numpy(onnx_y)
+
+    torch_y = encoder_layer(x, pos_emb)
+    assert torch.allclose(onnx_y, torch_y, atol=1e-05), (onnx_y - torch_y).abs().max()
+
+    print(onnx_y.abs().sum(), torch_y.abs().sum(), onnx_y.shape, torch_y.shape)
+
+    os.remove(filename)
+
+
+def test_zipformer_encoder():
+    filename = "zipformer_encoder.onnx"
+
+    opset_version = 13
+    N = 3
+    T = 15
+
+    d_model = 512
+    attention_dim = 192
+    nhead = 8
+    feedforward_dim = 1024
+    dropout = 0.1
+    cnn_module_kernel = 31
+    pos_dim = 4
+    num_encoder_layers = 12
+
+    warmup_batches = 4000.0
+    warmup_begin = warmup_batches / (num_encoder_layers + 1)
+    warmup_end = warmup_batches / (num_encoder_layers + 1)
+
+    x = torch.rand(N, T, d_model)
+
+    encoder_layer = ZipformerEncoderLayer(
+        d_model,
+        attention_dim,
+        nhead,
+        feedforward_dim,
+        dropout,
+        cnn_module_kernel,
+        pos_dim,
+    )
+    encoder = ZipformerEncoder(
+        encoder_layer, num_encoder_layers, dropout, warmup_begin, warmup_end
+    )
+    encoder.eval()
+    encoder = convert_scaled_to_non_scaled(encoder, inplace=True)
+
+    # jit_model = torch.jit.trace(encoder, (pos_emb))
+
+    torch_y = encoder(x)
+
+    torch.onnx.export(
+        encoder,
+        (x),
+        filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["x"],
+        output_names=["y"],
+        dynamic_axes={
+            "x": {0: "T", 1: "N"},
+            "y": {0: "T", 1: "N"},
+        },
+    )
+
+    options = ort.SessionOptions()
+    options.inter_op_num_threads = 1
+    options.intra_op_num_threads = 1
+
+    session = ort.InferenceSession(
+        filename,
+        sess_options=options,
+    )
+
+    input_nodes = session.get_inputs()
+    inputs = {
+        input_nodes[0].name: x.numpy(),
+    }
+    onnx_y = session.run(["y"], inputs)[0]
+    onnx_y = torch.from_numpy(onnx_y)
+
+    torch_y = encoder(x)
+    assert torch.allclose(onnx_y, torch_y, atol=1e-05), (onnx_y - torch_y).abs().max()
+
+    print(onnx_y.abs().sum(), torch_y.abs().sum(), onnx_y.shape, torch_y.shape)
+
+    os.remove(filename)
+
+
+def test_zipformer():
+    filename = "zipformer.onnx"
+    opset_version = 11
+    N = 3
+    T = 15
+    num_features = 80
+    x = torch.rand(N, T, num_features)
+    x_lens = torch.full((N,), fill_value=T, dtype=torch.int64)
+
+    zipformer = Zipformer(num_features=num_features)
+    zipformer.eval()
+    zipformer = convert_scaled_to_non_scaled(zipformer, inplace=True)
+
+    # jit_model = torch.jit.trace(zipformer, (x, x_lens))
+    torch.onnx.export(
+        zipformer,
+        (x, x_lens),
+        filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["x", "x_lens"],
+        output_names=["y", "y_lens"],
+        dynamic_axes={
+            "x": {0: "N", 1: "T"},
+            "x_lens": {0: "N"},
+            "y": {0: "N", 1: "T"},
+            "y_lens": {0: "N"},
+        },
+    )
+    options = ort.SessionOptions()
+    options.inter_op_num_threads = 1
+    options.intra_op_num_threads = 1
+
+    session = ort.InferenceSession(
+        filename,
+        sess_options=options,
+    )
+
+    input_nodes = session.get_inputs()
+    inputs = {
+        input_nodes[0].name: x.numpy(),
+        input_nodes[1].name: x_lens.numpy(),
+    }
+    onnx_y, onnx_y_lens = session.run(["y", "y_lens"], inputs)
+    onnx_y = torch.from_numpy(onnx_y)
+    onnx_y_lens = torch.from_numpy(onnx_y_lens)
+
+    torch_y, torch_y_lens = zipformer(x, x_lens)
+    assert torch.allclose(onnx_y, torch_y, atol=1e-05), (onnx_y - torch_y).abs().max()
+
+    assert torch.allclose(onnx_y_lens, torch_y_lens, atol=1e-05), (
+        (onnx_y_lens - torch_y_lens).abs().max()
+    )
+    print(onnx_y.abs().sum(), torch_y.abs().sum(), onnx_y.shape, torch_y.shape)
+    print(onnx_y_lens, torch_y_lens)
+
+    os.remove(filename)
+
+
+@torch.no_grad()
+def main():
+    test_conv2d_subsampling()
+    test_rel_pos()
+    test_zipformer_encoder_layer()
+    test_zipformer_encoder()
+    test_zipformer()
+
+
+if __name__ == "__main__":
+    torch.manual_seed(20221011)
+    main()
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7/zipformer.py b/egs/librispeech/ASR/pruned_transducer_stateless7/zipformer.py
index d18258085..b1717ec64 100644
--- a/egs/librispeech/ASR/pruned_transducer_stateless7/zipformer.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7/zipformer.py
@@ -210,7 +210,7 @@ class Zipformer(EncoderInterface):
              (num_frames, batch_size, encoder_dims0)
         """
         num_encoders = len(self.encoder_dims)
-        if torch.jit.is_scripting() or not self.training:
+        if torch.jit.is_scripting() or not self.training or torch.jit.is_tracing():
             return [1.0] * num_encoders
 
         (num_frames0, batch_size, _encoder_dims0) = x.shape
@@ -293,7 +293,7 @@ class Zipformer(EncoderInterface):
             k = self.skip_layers[i]
             if isinstance(k, int):
                 layer_skip_dropout_prob = self._get_layer_skip_dropout_prob()
-                if torch.jit.is_scripting():
+                if torch.jit.is_scripting() or torch.jit.is_tracing():
                     x = skip_module(outputs[k], x)
                 elif (not self.training) or random.random() > layer_skip_dropout_prob:
                     x = skip_module(outputs[k], x)
@@ -386,7 +386,7 @@ class ZipformerEncoderLayer(nn.Module):
         )
 
     def get_bypass_scale(self):
-        if torch.jit.is_scripting() or not self.training:
+        if torch.jit.is_scripting() or not self.training or torch.jit.is_tracing():
             return self.bypass_scale
         if random.random() < 0.1:
             # ensure we get grads if self.bypass_scale becomes out of range
@@ -407,7 +407,7 @@ class ZipformerEncoderLayer(nn.Module):
         # return dropout rate for the dynamic modules (self_attn, pooling, convolution); this
         # starts at 0.2 and rapidly decreases to 0.  Its purpose is to keep the training stable
         # at the beginning, by making the network focus on the feedforward modules.
-        if torch.jit.is_scripting() or not self.training:
+        if torch.jit.is_scripting() or not self.training or torch.jit.is_tracing():
             return 0.0
         warmup_period = 2000.0
         initial_dropout_rate = 0.2
@@ -452,12 +452,12 @@ class ZipformerEncoderLayer(nn.Module):
         dynamic_dropout = self.get_dynamic_dropout_rate()
 
         # pooling module
-        if torch.jit.is_scripting():
+        if torch.jit.is_scripting() or torch.jit.is_tracing():
             src = src + self.pooling(src, key_padding_mask=src_key_padding_mask)
         elif random.random() >= dynamic_dropout:
             src = src + self.pooling(src, key_padding_mask=src_key_padding_mask)
 
-        if torch.jit.is_scripting():
+        if torch.jit.is_scripting() or torch.jit.is_tracing():
             src_att, attn_weights = self.self_attn(
                 src,
                 pos_emb=pos_emb,
@@ -658,7 +658,7 @@ class ZipformerEncoder(nn.Module):
         pos_emb = self.encoder_pos(src)
         output = src
 
-        if torch.jit.is_scripting():
+        if torch.jit.is_scripting() or torch.jit.is_tracing():
             layers_to_drop = []
         else:
             rnd_seed = src.numel() + random.randint(0, 1000)
@@ -667,7 +667,7 @@ class ZipformerEncoder(nn.Module):
         output = output * feature_mask
 
         for i, mod in enumerate(self.layers):
-            if not torch.jit.is_scripting():
+            if not torch.jit.is_scripting() and not torch.jit.is_tracing():
                 if i in layers_to_drop:
                     continue
             output = mod(
@@ -864,7 +864,7 @@ class SimpleCombiner(torch.nn.Module):
         assert src1.shape[:-1] == src2.shape[:-1], (src1.shape, src2.shape)
 
         weight1 = self.weight1
-        if not torch.jit.is_scripting():
+        if not torch.jit.is_scripting() and not torch.jit.is_tracing():
             if (
                 self.training
                 and random.random() < 0.25
@@ -1258,21 +1258,31 @@ class RelPositionMultiheadAttention(nn.Module):
         # the following .as_strided() expression converts the last axis of pos_weights from relative
         # to absolute position.  I don't know whether I might have got the time-offsets backwards or
         # not, but let this code define which way round it is supposed to be.
-        pos_weights = pos_weights.as_strided(
-            (bsz, num_heads, seq_len, seq_len),
-            (
-                pos_weights.stride(0),
-                pos_weights.stride(1),
-                pos_weights.stride(2) - pos_weights.stride(3),
-                pos_weights.stride(3),
-            ),
-            storage_offset=pos_weights.stride(3) * (seq_len - 1),
-        )
+        if torch.jit.is_tracing():
+            (batch_size, num_heads, time1, n) = pos_weights.shape
+            rows = torch.arange(start=time1 - 1, end=-1, step=-1)
+            cols = torch.arange(seq_len)
+            rows = rows.repeat(batch_size * num_heads).unsqueeze(-1)
+            indexes = rows + cols
+            pos_weights = pos_weights.reshape(-1, n)
+            pos_weights = torch.gather(pos_weights, dim=1, index=indexes)
+            pos_weights = pos_weights.reshape(batch_size, num_heads, time1, seq_len)
+        else:
+            pos_weights = pos_weights.as_strided(
+                (bsz, num_heads, seq_len, seq_len),
+                (
+                    pos_weights.stride(0),
+                    pos_weights.stride(1),
+                    pos_weights.stride(2) - pos_weights.stride(3),
+                    pos_weights.stride(3),
+                ),
+                storage_offset=pos_weights.stride(3) * (seq_len - 1),
+            )
 
         # caution: they are really scores at this point.
         attn_output_weights = torch.matmul(q, k) + pos_weights
 
-        if not torch.jit.is_scripting():
+        if not torch.jit.is_scripting() and not torch.jit.is_tracing():
             if training and random.random() < 0.1:
                 # This is a harder way of limiting the attention scores to not be too large.
                 # It incurs a penalty if any of them has an absolute value greater than 50.0.
@@ -1383,7 +1393,7 @@ class RelPositionMultiheadAttention(nn.Module):
         # now v: (bsz * num_heads, seq_len, head_dim // 2)
         attn_output = torch.bmm(attn_weights, v)
 
-        if not torch.jit.is_scripting():
+        if not torch.jit.is_scripting() and not torch.jit.is_tracing():
             if random.random() < 0.001 or __name__ == "__main__":
                 self._print_attn_stats(attn_weights, attn_output)
 
@@ -1458,7 +1468,10 @@ class PoolingModule(nn.Module):
            a Tensor of shape (1, N, C)
         """
         if key_padding_mask is not None:
-            pooling_mask = key_padding_mask.logical_not().to(x.dtype)  # (N, T)
+            if torch.jit.is_tracing():
+                pooling_mask = (~key_padding_mask).to(x.dtype)
+            else:
+                pooling_mask = key_padding_mask.logical_not().to(x.dtype)  # (N, T)
             pooling_mask = pooling_mask / pooling_mask.sum(dim=1, keepdim=True)
             pooling_mask = pooling_mask.transpose(0, 1).contiguous().unsqueeze(-1)
             # now pooling_mask: (T, N, 1)