diff --git a/docs/design_docs/datanode_flowgraph_recovery_design_0604_2021.md b/docs/design_docs/datanode_flowgraph_recovery_design_0604_2021.md
index 214ee3a337..c7fe3ae27f 100644
--- a/docs/design_docs/datanode_flowgraph_recovery_design_0604_2021.md
+++ b/docs/design_docs/datanode_flowgraph_recovery_design_0604_2021.md
@@ -5,8 +5,8 @@ update: 6.21.2021, by [Goose](https://github.com/XuanYang-cn)
 
 ## 1. Common Sense
 
-A. One message stream to one vchannel, so there are one start position and one end position in one message pack
-B. Only when datanode flushes, datanode will update every segment's position
+A. One message stream to one vchannel, so there are one start position and one end position in one message pack.
+B. Only when datanode flushes, datanode will update every segment's position.
 An optimization: update position of
 
 - a. Current flushing segment