diff --git a/paddlespeech/t2s/exps/fastspeech2/gen_gta_mel.py b/paddlespeech/t2s/exps/fastspeech2/gen_gta_mel.py
index 3fded29b12a180d3153d42ecb4dc810ce25fa900..4c92ad1cc46ee22e165f560eb4095d4044a559fe 100644
--- a/paddlespeech/t2s/exps/fastspeech2/gen_gta_mel.py
+++ b/paddlespeech/t2s/exps/fastspeech2/gen_gta_mel.py
@@ -13,7 +13,6 @@
 # limitations under the License.
 # generate mels using durations.txt
 # for mb melgan finetune
-# 长度和原本的 mel 不一致怎么办？
 import argparse
 import os
 from pathlib import Path
diff --git a/paddlespeech/t2s/models/hifigan/hifigan.py b/paddlespeech/t2s/models/hifigan/hifigan.py
index 116376eceb4ef5c7847325e0a20b088641cb153c..ac5ff204fae661dbc159f53970389ce3287a7b9f 100644
--- a/paddlespeech/t2s/models/hifigan/hifigan.py
+++ b/paddlespeech/t2s/models/hifigan/hifigan.py
@@ -1,7 +1,17 @@
-# -*- coding: utf-8 -*-
-"""HiFi-GAN Modules.
-This code is based on https://github.com/jik876/hifi-gan.
-"""
+# Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+#
+# 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 code is based on https://github.com/jik876/hifi-gan.
 import copy
 from typing import Any
 from typing import Dict
diff --git a/paddlespeech/t2s/models/tacotron2/tacotron2.py b/paddlespeech/t2s/models/tacotron2/tacotron2.py
index abb691b4dcd884550d0ba16a3eae783f4fd753fc..7b306e4820de10db9ae8551fffe62ab50d055905 100644
--- a/paddlespeech/t2s/models/tacotron2/tacotron2.py
+++ b/paddlespeech/t2s/models/tacotron2/tacotron2.py
@@ -11,6 +11,7 @@
 # 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.
+# Modified from espnet(https://github.com/espnet/espnet)
 """Tacotron 2 related modules for paddle"""
 import logging
 from typing import Dict
diff --git a/paddlespeech/t2s/models/wavernn/wavernn.py b/paddlespeech/t2s/models/wavernn/wavernn.py
index 9590704328b757b27a6626e8e3a5c675da41c8e0..b4b8b48091ff2ad4f2774af2662afd5e0a48b79c 100644
--- a/paddlespeech/t2s/models/wavernn/wavernn.py
+++ b/paddlespeech/t2s/models/wavernn/wavernn.py
@@ -11,6 +11,7 @@
 # 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.
+# Modified from https://github.com/fatchord/WaveRNN
 import sys
 import time
 from typing import List