diff --git a/internal/service/welfare_activity/activity.go b/internal/service/welfare_activity/activity.go
index c7f19be..b99449d 100644
--- a/internal/service/welfare_activity/activity.go
+++ b/internal/service/welfare_activity/activity.go
@@ -123,12 +123,16 @@ func (s *service) ListActivities(ctx context.Context, req ListActivitiesRequest)
 	if req.PageSize > 100 {
 		req.PageSize = 100
 	}
+	now := time.Now()
 	db := s.repo.GetDbR().WithContext(ctx).Model(&Activity{}).Where("deleted_at IS NULL")
 	if req.Type != "" {
 		db = db.Where("type = ?", req.Type)
 	}
 	if req.Status != "" {
 		db = db.Where("status = ?", req.Status)
+		if req.Status == StatusActive {
+			db = db.Where("start_time <= ? AND end_time >= ? AND draw_time >= ?", now, now, now)
+		}
 	}
 	if strings.TrimSpace(req.Title) != "" {
 		db = db.Where("title LIKE ?", "%"+strings.TrimSpace(req.Title)+"%")
@@ -157,6 +161,9 @@ func (s *service) GetActivity(ctx context.Context, id int64, userID int64) (*Act
 	if err := s.repo.GetDbR().WithContext(ctx).Where("id = ? AND deleted_at IS NULL", id).First(&item).Error; err != nil {
 		return nil, err
 	}
+	if userID <= 0 && item.Status == StatusActive && time.Now().Before(item.StartTime) {
+		return nil, errors.New("活动未开始")
+	}
 	detail := &ActivityDetail{Activity: item}
 	s.repo.GetDbR().WithContext(ctx).Where("activity_id = ?", id).Order("sort ASC, id ASC").Find(&detail.Prizes)
 	s.fillPrizeMeta(ctx, detail.Prizes)
@@ -172,7 +179,7 @@ func (s *service) GetActivity(ctx context.Context, id int64, userID int64) (*Act
 	if userID > 0 {
 		start, end, period := periodRange(item.Type, time.Now())
 		detail.CurrentPaid, _ = s.sumPaidAmount(ctx, userID, start, end)
-		detail.CanJoin = detail.CurrentPaid >= item.ThresholdAmount && item.Status == StatusActive && time.Now().Before(item.DrawTime) && time.Now().Before(item.EndTime)
+		detail.CanJoin = isJoinWindowOpen(item, time.Now()) && detail.CurrentPaid >= item.ThresholdAmount
 		var count int64
 		s.repo.GetDbR().WithContext(ctx).Model(&Participant{}).Where("activity_id = ? AND user_id = ? AND period_key = ?", id, userID, period).Count(&count)
 		detail.Joined = count > 0
diff --git a/internal/service/welfare_activity/participant.go b/internal/service/welfare_activity/participant.go
index 9a52ed6..00a339a 100644
--- a/internal/service/welfare_activity/participant.go
+++ b/internal/service/welfare_activity/participant.go
@@ -16,10 +16,10 @@ func (s *service) Join(ctx context.Context, activityID int64, userID int64) erro
 		return err
 	}
 	now := time.Now()
-	if activity.Status != StatusActive {
-		return errors.New("活动未开放参与")
-	}
-	if now.Before(activity.StartTime) || now.After(activity.EndTime) || now.After(activity.DrawTime) {
+	if !isJoinWindowOpen(activity, now) {
+		if now.Before(activity.StartTime) {
+			return errors.New("活动未开始")
+		}
 		return errors.New("当前不在活动参与时间内")
 	}
 	start, end, period := periodRange(activity.Type, now)
diff --git a/internal/service/welfare_activity/welfare_activity.go b/internal/service/welfare_activity/welfare_activity.go
index c64d493..30863fc 100644
--- a/internal/service/welfare_activity/welfare_activity.go
+++ b/internal/service/welfare_activity/welfare_activity.go
@@ -45,3 +45,16 @@ type service struct {
 func New(log logger.CustomLogger, repo mysql.Repo) Service {
 	return &service{logger: log, repo: repo, userSvc: usersvc.New(log, repo)}
 }
+
+func isJoinWindowOpen(activity Activity, now time.Time) bool {
+	if activity.Status != StatusActive {
+		return false
+	}
+	if now.Before(activity.StartTime) {
+		return false
+	}
+	if now.After(activity.EndTime) || now.After(activity.DrawTime) {
+		return false
+	}
+	return true
+}