diff --git a/doc/howto/read_source.md b/doc/howto/read_source.md
index 383acb0c8251043c3c6bbf309d2e07bf0074cd4f..e4211abb3be9cace80bc14dbe3db3e0a31221dd0 100644
--- a/doc/howto/read_source.md
+++ b/doc/howto/read_source.md
@@ -6,10 +6,10 @@ Core: https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/framework
 
 Operator: https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/operators
 
-Optimizer: https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/optimizer
-
 Memory: https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/memory
 
+Platform: https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/platform
+
 # Compile Time
 
 The following **defines** the NN. The definition goes into this [protocol buffer](https://github.com/PaddlePaddle/Paddle/blob/develop/paddle/framework/framework.proto).