diff --git a/python/paddle/fluid/async_executor.py b/python/paddle/fluid/async_executor.py
index fe2e9b8f12d3cf07af56d069f6737ddb10273d61..bd32138651f98f51a469a8ed991f52ee41b0c45d 100644
--- a/python/paddle/fluid/async_executor.py
+++ b/python/paddle/fluid/async_executor.py
@@ -177,7 +177,7 @@ class AsyncExecutor(object):
             >>> exe = fluid.AsyncExecutor()
             >>> exe.download_data("/xxx/xxx/xx/",
             >>>                   "./data", "afs://            
-            >>>  xxx.xxx.xxx.xxx:9901", "xxx,yyy")
+            >>>  xxx.xxx.xxx.xxx:9901", "xxx,yyy") 
         Args:
             afs_path(str): afs_path defined by users
             local_path(str): download data path
diff --git a/python/requirements.txt b/python/requirements.txt
index 2f81d85df0626b294f4d861706b5c1b7ec9841d5..5d64674fe02e232c99875825655a6c5c04b9db9d 100644
--- a/python/requirements.txt
+++ b/python/requirements.txt
@@ -9,3 +9,4 @@ Pillow
 nltk>=3.2.2
 graphviz
 six
+mpi4py=3.0.0