diff --git a/docs/design/LLD-预约模块详细设计.md b/docs/design/LLD-预约模块详细设计.md
index 53ab227..87b2c15 100644
--- a/docs/design/LLD-预约模块详细设计.md
+++ b/docs/design/LLD-预约模块详细设计.md
@@ -68,8 +68,6 @@ graph TB
 
 ### 2.1 实体关系图
 
-### 2.1 实体关系图
-
 ```mermaid
 erDiagram
     coach ||--o{ booking_slot : coaches