diff --git a/docs/design_docs/retrieve_entity.md b/docs/design_docs/retrieve_entity.md
index c281e14e4c8ed96cadc411ed33f078471b35a377..3941587be6c9ac2b5c02bd3a65ed60a9f66cf2b3 100644
--- a/docs/design_docs/retrieve_entity.md
+++ b/docs/design_docs/retrieve_entity.md
@@ -4,8 +4,8 @@
 
 In Milvus, one entity encapsulates multiple vectors and scalars.
 
-When creating a collection, you can specify using the primary key generated automatically, or using the user-provided primary key. 
-If a user sets to use the user-provided primary key, each entity inserted must contain the primary key field. Otherwise, the insertion fails. 
+When creating a collection, you can specify using the primary key generated automatically, or using the user-provided primary key.
+If a user sets to use the user-provided primary key, each entity inserted must contain the primary key field. Otherwise, the insertion fails.
 The primary keys will be returned after the insertion request is successful.
 
 Milvus currently only supports primary keys of int64 type.