diff --git a/docs/developer_guides/appendix_b_api_reference.md b/docs/developer_guides/appendix_b_api_reference.md
index c3086f4ab6..d7ba822418 100644
--- a/docs/developer_guides/appendix_b_api_reference.md
+++ b/docs/developer_guides/appendix_b_api_reference.md
@@ -834,7 +834,7 @@ message Status {
 }
 ```
 
-**Status** represents the server error code. It doesn't contain grpc error but contains the server error code. We can get the executing result in common status. **error_code** is an enum type to distinguish the executing error type. The total Errorcode is shown in the last of this code. And the **reason** field is a string to describes the detailed error.
+**Status** represents the server error code. It doesn't contain grpc error but contains the server error code. We can get the executing result in common status. **error_code** is an enum type to distinguish the executing error type. The total Errorcode is shown in the last of this code. And the **reason** field is a string to describe error detail.
 
 ###### 3.3.2 DescribeIndex