diff --git a/src/main/java/com/yunhai/familyactivity/service/impl/ActivityService.java b/src/main/java/com/yunhai/familyactivity/service/impl/ActivityService.java
index b37dd30..e17f1ad 100644
--- a/src/main/java/com/yunhai/familyactivity/service/impl/ActivityService.java
+++ b/src/main/java/com/yunhai/familyactivity/service/impl/ActivityService.java
@@ -1201,11 +1201,15 @@ public class ActivityService implements IActivityService {
         activityReadRepository.save(read);
     }
 
-    /** confirm 模式：家长打开活动即自动确认（未回执 → 已确认） */
+    /** confirm 模式：家长打开活动即自动确认（未回执 → 已确认）。
+     *  仅报名截止时间内生效（活动处于「报名中」态）：超过截止时间（转「已截止/已结束」）后打开只标已读，不再自动确认。 */
     private void autoConfirmIfNeeded(Activity activity, Integer studentId) {
         if (!ReceiptModeEnum.CONFIRM.getCode().equalsIgnoreCase(activity.getReceiptMode())) {
             return;
         }
+        if (deriveStatus(activity, LocalDateTime.now()) != ActivityStatusEnum.SIGNUP) {
+            return;
+        }
         activitySignupRepository.findByActivityIdAndStudentId(activity.getId(), studentId)
                 .ifPresent(record -> {
                     if (SignupStatusEnum.NONE.getCode().equalsIgnoreCase(record.getStatus())) {