diff --git a/egs/icmcasr/ASR/local/compile_lg.py b/egs/icmcasr/ASR/local/compile_lg.py
new file mode 100644
index 000000000..709b14070
--- /dev/null
+++ b/egs/icmcasr/ASR/local/compile_lg.py
@@ -0,0 +1,147 @@
+#!/usr/bin/env python3
+# Copyright    2021  Xiaomi Corp.        (authors: Fangjun Kuang, Wei Kang)
+#
+# 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 takes as input lang_dir and generates LG from
+
+    - L, the lexicon, built from lang_dir/L_disambig.pt
+
+        Caution: We use a lexicon that contains disambiguation symbols
+
+    - G, the LM, built from data/lm/G_3_gram.fst.txt
+
+The generated LG is saved in $lang_dir/LG.pt
+"""
+import argparse
+import logging
+from pathlib import Path
+
+import k2
+import torch
+
+from icefall.lexicon import Lexicon
+
+
+def get_args():
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--lang-dir",
+        type=str,
+        help="""Input and output directory.
+        """,
+    )
+    parser.add_argument(
+        "--lm",
+        type=str,
+        default="G_3_gram",
+        help="""Stem name for LM used in HLG compiling.
+        """,
+    )
+
+    return parser.parse_args()
+
+
+def compile_LG(lang_dir: str, lm: str = "G_3_gram") -> k2.Fsa:
+    """
+    Args:
+      lang_dir:
+        The language directory, e.g., data/lang_phone or data/lang_bpe_5000.
+
+    Return:
+      An FSA representing LG.
+    """
+    lexicon = Lexicon(lang_dir)
+    L = k2.Fsa.from_dict(torch.load(f"{lang_dir}/L_disambig.pt"))
+
+    if Path(f"data/lm/{lm}.pt").is_file():
+        logging.info(f"Loading pre-compiled {lm}")
+        d = torch.load(f"data/lm/{lm}.pt")
+        G = k2.Fsa.from_dict(d)
+    else:
+        logging.info(f"Loading {lm}.fst.txt")
+        with open(f"data/lm/{lm}.fst.txt") as f:
+            G = k2.Fsa.from_openfst(f.read(), acceptor=False)
+            torch.save(G.as_dict(), f"data/lm/{lm}.pt")
+
+    first_token_disambig_id = lexicon.token_table["#0"]
+    first_word_disambig_id = lexicon.word_table["#0"]
+
+    L = k2.arc_sort(L)
+    G = k2.arc_sort(G)
+
+    logging.info("Intersecting L and G")
+    LG = k2.compose(L, G)
+    logging.info(f"LG shape: {LG.shape}")
+
+    logging.info("Connecting LG")
+    LG = k2.connect(LG)
+    logging.info(f"LG shape after k2.connect: {LG.shape}")
+
+    logging.info(type(LG.aux_labels))
+    logging.info("Determinizing LG")
+
+    LG = k2.determinize(LG, k2.DeterminizeWeightPushingType.kLogWeightPushing)
+    logging.info(type(LG.aux_labels))
+
+    logging.info("Connecting LG after k2.determinize")
+    LG = k2.connect(LG)
+
+    logging.info("Removing disambiguation symbols on LG")
+
+    # LG.labels[LG.labels >= first_token_disambig_id] = 0
+    # see https://github.com/k2-fsa/k2/pull/1140
+    labels = LG.labels
+    labels[labels >= first_token_disambig_id] = 0
+    LG.labels = labels
+
+    assert isinstance(LG.aux_labels, k2.RaggedTensor)
+    LG.aux_labels.values[LG.aux_labels.values >= first_word_disambig_id] = 0
+
+    LG = k2.remove_epsilon(LG)
+    logging.info(f"LG shape after k2.remove_epsilon: {LG.shape}")
+
+    LG = k2.connect(LG)
+    LG.aux_labels = LG.aux_labels.remove_values_eq(0)
+
+    logging.info("Arc sorting LG")
+    LG = k2.arc_sort(LG)
+
+    return LG
+
+
+def main():
+    args = get_args()
+    lang_dir = Path(args.lang_dir)
+
+    if (lang_dir / "LG.pt").is_file():
+        logging.info(f"{lang_dir}/LG.pt already exists - skipping")
+        return
+
+    logging.info(f"Processing {lang_dir}")
+
+    LG = compile_LG(lang_dir, args.lm)
+    logging.info(f"Saving LG.pt to {lang_dir}")
+    torch.save(LG.as_dict(), f"{lang_dir}/LG.pt")
+
+
+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/icmcasr/ASR/local/text2segments.py b/egs/icmcasr/ASR/local/text2segments.py
new file mode 120000
index 000000000..7d68a39c3
--- /dev/null
+++ b/egs/icmcasr/ASR/local/text2segments.py
@@ -0,0 +1 @@
+../../../wenetspeech/ASR/local/text2segments.py
\ No newline at end of file
diff --git a/egs/icmcasr/ASR/local/text2token.py b/egs/icmcasr/ASR/local/text2token.py
new file mode 120000
index 000000000..ce5cfd537
--- /dev/null
+++ b/egs/icmcasr/ASR/local/text2token.py
@@ -0,0 +1 @@
+../../../wenetspeech/ASR/local/text2token.py
\ No newline at end of file
diff --git a/egs/icmcasr/ASR/prepare.sh b/egs/icmcasr/ASR/prepare.sh
index 1de9562a9..77bad4adb 100755
--- a/egs/icmcasr/ASR/prepare.sh
+++ b/egs/icmcasr/ASR/prepare.sh
@@ -6,8 +6,8 @@ export PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python
 set -eou pipefail
 
 nj=15
-stage=4
-stop_stage=4
+stage=8
+stop_stage=8
 
 # We assume dl_dir (download dir) contains the following
 # directories and files. If not, they will be downloaded
@@ -34,9 +34,9 @@ dl_dir=$PWD/download
 # It will generate data/lang_bbpe_xxx,
 # data/lang_bbpe_yyy if the array contains xxx, yyy
 vocab_sizes=(
-  # 2000
+  2000
   # 1000
-  500
+  # 500
 )
 
 # All files generated by this script are saved in "data".
@@ -103,19 +103,91 @@ if [ $stage -le 5 ] && [ $stop_stage -ge 5 ]; then
   fi
 fi
 
-lang_phone_dir=data/lang_phone
+lang_char_dir=data/lang_char
 if [ $stage -le 6 ] && [ $stop_stage -ge 6 ]; then
-  log "Stage 6: Prepare G.fst"
-  mkdir -p $lang_phone_dir
+  log "Stage 6: Prepare char based lang"
+  mkdir -p $lang_char_dir
 
-  (echo '!SIL SIL'; echo '<SPOKEN_NOISE> SPN'; echo '<UNK> SPN'; ) |
-    cat - $dl_dir/icmcasr/resource_icmcasr/lexicon.txt |
-    sort | uniq > $lang_phone_dir/lexicon.txt
+  if ! which jq; then
+      echo "This script is intended to be used with jq but you have not installed jq
+      Note: in Linux, you can install jq with the following command:
+      1. wget -O jq https://github.com/stedolan/jq/releases/download/jq-1.6/jq-linux64
+      2. chmod +x ./jq
+      3. cp jq /usr/bin" && exit 1
+  fi
+  if [ ! -f $lang_char_dir/text ] || [ ! -s $lang_char_dir/text ]; then
+    log "Prepare text."
+    gunzip -c data/manifests/icmcasr-ihm_supervisions_train.jsonl.gz \
+      | jq '.text' | sed 's/"//g' \
+      | ./local/text2token.py -t "char" > $lang_char_dir/text
+  fi
 
-  ./local/generate_unique_lexicon.py --lang-dir $lang_phone_dir
-
-  if [ ! -f $lang_phone_dir/L_disambig.pt ]; then
-    ./local/prepare_lang.py --lang-dir $lang_phone_dir
+  # The implementation of chinese word segmentation for text,
+  # and it will take about 15 minutes.
+  if [ ! -f $lang_char_dir/text_words_segmentation ]; then
+    python3 ./local/text2segments.py \
+      --num-process $nj \
+      --input-file $lang_char_dir/text \
+      --output-file $lang_char_dir/text_words_segmentation
+  fi
+  if [ -f $lang_char_dir/words.txt ]; then
+    cd $lang_char_dir
+    ln -s ../../../../wenetspeech/ASR/data/lang_char/words.txt .
+    cd ..
+  else
+    log "Abort! Please run ../../wenetspeech/ASR/prepare.sh"
+    exit 1
   fi
 fi
 
+if [ $stage -le 7 ] && [ $stop_stage -ge 7 ]; then
+  log "Stage 7: Prepare G"
+  if [ ! -f $lang_char_dir/3-gram.unpruned.arpa ]; then
+    python3 ./shared/make_kn_lm.py \
+      -ngram-order 3 \
+      -text $lang_char_dir/text_words_segmentation \
+      -lm $lang_char_dir/3-gram.unpruned.arpa
+  fi
+
+  mkdir -p data/lm
+  if [ ! -f data/lm/G_3_gram.fst.txt ]; then
+    # It is used in building LG
+    python3 -m kaldilm \
+      --read-symbol-table="$lang_char_dir/words.txt" \
+      --disambig-symbol='#0' \
+      --max-order=3 \
+      $lang_char_dir/3-gram.unpruned.arpa > data/lm/G_3_gram.fst.txt
+  fi
+
+  if [ ! -f $lang_char_dir/5-gram.unpruned.arpa ]; then
+    python3 ./shared/make_kn_lm.py \
+      -ngram-order 5 \
+      -text $lang_char_dir/text_words_segmentation \
+      -lm $lang_char_dir/5-gram.unpruned.arpa
+  fi
+
+  if [ ! -f data/lm/G_5_gram.fst.txt ]; then
+    # It is used in building LG
+    python3 -m kaldilm \
+      --read-symbol-table="$lang_char_dir/words.txt" \
+      --disambig-symbol='#0' \
+      --max-order=5 \
+      $lang_char_dir/5-gram.unpruned.arpa > data/lm/G_5_gram.fst.txt
+  fi
+fi
+
+if [ $stage -le 8 ] && [ $stop_stage -ge 8 ]; then
+  log "Stage 15: Compile LG"
+  if [ ! -d data/lang_bpe_2000/ ]; then
+    log "Abort! Please run ../../multi_zh-hans/ASR/prepare.sh"
+    exit 1
+    cd data
+    ln -s ../../../../multi_zh-hans/ASR/data/lang_bpe_2000 .
+    cd ..
+  else
+    log "data/lang_bpe_2000/ exists"
+  fi
+  lang_dir=data/lang_bpe_2000
+  python3 ./local/compile_lg.py --lang-dir $lang_dir
+  #python3 ./local/compile_lg.py --lang-dir $lang_dir --lm G_5_gram
+fi
\ No newline at end of file