diff --git a/实体关系.md b/实体关系.md
index a6a0567..d7851c0 100644
--- a/实体关系.md
+++ b/实体关系.md
@@ -62,7 +62,7 @@ class Group {
     public int Id { get; set; } //Id、GroupId、Group_id
 
     public int ParentId { get; set; } //ParentId、Parent_id
-    public Tag Parent { get; set; }
+    public Group Parent { get; set; }
 
     public ICollection<Group> Childs { get; set; }
 }