diff --git a/egs/tal_csasr/ASR/lstm_transducer_stateless3/export-for-ncnn.py b/egs/tal_csasr/ASR/lstm_transducer_stateless3/export-for-ncnn.py
index 7982ace68..d7bd3d9d9 100755
--- a/egs/tal_csasr/ASR/lstm_transducer_stateless3/export-for-ncnn.py
+++ b/egs/tal_csasr/ASR/lstm_transducer_stateless3/export-for-ncnn.py
@@ -60,6 +60,7 @@ from icefall.checkpoint import (
     find_checkpoints,
     load_checkpoint,
 )
+from icefall.lexicon import Lexicon
 from icefall.utils import setup_logger, str2bool
 
 
@@ -106,10 +107,10 @@ def get_parser():
     )
 
     parser.add_argument(
-        "--bpe-model",
+        "--lang-dir",
         type=str,
-        default="data/lang_bpe_500/bpe.model",
-        help="Path to the BPE model",
+        default="data/lang_char",
+        help="Path to the lang",
     )
 
     parser.add_argument(
@@ -221,12 +222,10 @@ def main():
 
     logging.info(f"device: {device}")
 
-    sp = spm.SentencePieceProcessor()
-    sp.load(params.bpe_model)
+    lexicon = Lexicon(params.lang_dir)
 
-    # <blk> is defined in local/train_bpe_model.py
-    params.blank_id = sp.piece_to_id("<blk>")
-    params.vocab_size = sp.get_piece_size()
+    params.blank_id = lexicon.token_table["<blk>"]
+    params.vocab_size = max(lexicon.tokens) + 1
 
     logging.info(params)