diff --git a/doc/NEW_WEB_SERVICE.md b/doc/NEW_WEB_SERVICE.md
index b76c6d42e25c67107367da4213e04f774c05dd85..63f62a774d914c7271bfed1508881e04f74f2ca8 100644
--- a/doc/NEW_WEB_SERVICE.md
+++ b/doc/NEW_WEB_SERVICE.md
@@ -11,7 +11,7 @@ Paddle Serving implements the [WebService](https://github.com/PaddlePaddle/Servi
 ```python
 class WebService(object):
   
-		def preprocess(self, feed={}, fetch=[]):
+    def preprocess(self, feed={}, fetch=[]):
         return feed, fetch
     def postprocess(self, feed={}, fetch=[], fetch_map=None):
         return fetch_map
diff --git a/doc/NEW_WEB_SERVICE_CN.md b/doc/NEW_WEB_SERVICE_CN.md
index 067780e39ee458661d49fba2cc88ec481da11a0e..a179701644c06f3e93ebe0653fb262dbbfc60066 100644
--- a/doc/NEW_WEB_SERVICE_CN.md
+++ b/doc/NEW_WEB_SERVICE_CN.md
@@ -11,7 +11,7 @@ Paddle Serving实现了[WebService](https://github.com/PaddlePaddle/Serving/blob
 ```python
 class WebService(object):
   
-		def preprocess(self, feed={}, fetch=[]):
+    def preprocess(self, feed={}, fetch=[]):
         return feed, fetch
     def postprocess(self, feed={}, fetch=[], fetch_map=None):
         return fetch_map