diff --git a/docs/en/user_guides/1_config.md b/docs/en/user_guides/1_config.md
index 54c1f3636..291c488e8 100644
--- a/docs/en/user_guides/1_config.md
+++ b/docs/en/user_guides/1_config.md
@@ -521,7 +521,7 @@ if __name__ == '__main__':
     main()
 ```
 
-A example config file `demo_config.py` as follows:
+An example config file `demo_config.py` as follows:
 
 ```python
 backbone = dict(