diff --git a/crates/erp-diary/src/service/class_service.rs b/crates/erp-diary/src/service/class_service.rs
index aedd09f..a198758 100644
--- a/crates/erp-diary/src/service/class_service.rs
+++ b/crates/erp-diary/src/service/class_service.rs
@@ -193,11 +193,12 @@ impl ClassService {
         member_model.insert(db).await?;
 
         // 6. 更新 member_count
+        let current_count = class_model.member_count;
+        let current_version = class_model.version;
         let mut active_class: school_class::ActiveModel = class_model.into();
-        let new_count = active_class.member_count.unwrap() + 1;
-        active_class.member_count = Set(new_count);
+        active_class.member_count = Set(current_count + 1);
         active_class.updated_at = Set(now);
-        active_class.version = Set(active_class.version.unwrap() + 1);
+        active_class.version = Set(current_version + 1);
         let updated_class = active_class.update(db).await?;
 
         // 7. 成功加入 → 清除错误计数