diff --git a/.travis.yml b/.travis.yml
index 75c2c1351..4ca3f5a46 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -13,11 +13,13 @@ addons:
   apt:
     packages:
       - git
-      - python
-      - python-pip
-      - python2.7-dev
+      - python3
+      - python3-pip
+      - python3-dev
 
 before_install:
+  -  python --version
+  -  pip --version
   -  sudo pip install -U virtualenv pre-commit pip
   -  docker pull paddlepaddle/paddle:latest
 
diff --git a/.travis/unittest.sh b/.travis/unittest.sh
index f27dc481a..e42764368 100755
--- a/.travis/unittest.sh
+++ b/.travis/unittest.sh
@@ -17,7 +17,7 @@ unittest(){
     fi
     find . -name 'tests' -type d -print0 | \
         xargs -0 -I{} -n1 bash -c \
-        'python -m unittest discover -v -s {}'
+        'python3 -m unittest discover -v -s {}'
     cd - > /dev/null
 }
 
diff --git a/decoders/swig_wrapper.py b/decoders/swig_wrapper.py
index 49215722d..b32893b92 100644
--- a/decoders/swig_wrapper.py
+++ b/decoders/swig_wrapper.py
@@ -114,8 +114,6 @@ def ctc_beam_search_decoder_batch(probs_split,
     batch_beam_results = swig_decoders.ctc_beam_search_decoder_batch(
         probs_split, vocabulary, beam_size, num_processes, cutoff_prob,
         cutoff_top_n, ext_scoring_func)
-    batch_beam_results = [
-        [(res[0], res[1]) for res in beam_results]
-        for beam_results in batch_beam_results
-    ]
+    batch_beam_results = [[(res[0], res[1]) for res in beam_results]
+                          for beam_results in batch_beam_results]
     return batch_beam_results
diff --git a/model_utils/network.py b/model_utils/network.py
index 6e29eb6e4..b8812e609 100644
--- a/model_utils/network.py
+++ b/model_utils/network.py
@@ -1,4 +1,3 @@
-
 import collections
 import paddle.fluid as fluid
 import numpy as np