diff --git a/internal/rpc/rtc/signal.go b/internal/rpc/rtc/signal.go
index a46aa3f27..be4b8ea50 100644
--- a/internal/rpc/rtc/signal.go
+++ b/internal/rpc/rtc/signal.go
@@ -108,6 +108,17 @@ func (s *rtcServer) handleInvite(ctx context.Context, req *rtc.SignalInviteReq,
 		}
 	}
 
+	// 检测哪些被叫用户正忙（已在通话中），记录到 BusyLineUserIDList
+	busyUserIDs, err := s.db.GetBusyUserIDs(ctx, inv.InviteeUserIDList)
+	if err != nil {
+		log.ZWarn(ctx, "handleInvite: GetBusyUserIDs failed (non-fatal)", err)
+	}
+	busySet := make(map[string]struct{}, len(busyUserIDs))
+	for _, uid := range busyUserIDs {
+		busySet[uid] = struct{}{}
+	}
+	inv.BusyLineUserIDList = busyUserIDs
+
 	// 从主叫用户资料获取铃声 URL，注入到邀请信息中，被叫方收到后播放主叫方铃声
 	if inviterInfo, err := s.userClient.GetUserInfo(ctx, req.UserID); err == nil && inviterInfo.CallRingtoneURL != "" {
 		inv.CallerRingtoneURL = inviterInfo.CallRingtoneURL
@@ -151,6 +162,10 @@ func (s *rtcServer) handleInvite(ctx context.Context, req *rtc.SignalInviteReq,
 	}
 
 	for _, inviteeID := range inv.InviteeUserIDList {
+		if _, busy := busySet[inviteeID]; busy {
+			log.ZInfo(ctx, "handleInvite: skip busy invitee", "inviteeID", inviteeID)
+			continue
+		}
 		log.ZInfo(ctx, "sendSignalingNotification to invitee", "sendID", req.UserID, "recvID", inviteeID)
 		if err := s.sendSignalingNotification(ctx, req.UserID, inviteeID, int32(constant.SingleChatType), req.OfflinePushInfo, content); err != nil {
 			log.ZError(ctx, "sendSignalingNotification to invitee failed", err, "inviteeID", inviteeID)
@@ -160,10 +175,11 @@ func (s *rtcServer) handleInvite(ctx context.Context, req *rtc.SignalInviteReq,
 
 	log.ZDebug(ctx, "handleInvite", "token", token, "roomID", inv.RoomID, "liveURL", s.config.RpcConfig.LiveKit.ExternalAddress)
 	return &rtc.SignalInviteResp{
-		Token:             token,
-		RoomID:            inv.RoomID,
-		LiveURL:           s.config.RpcConfig.LiveKit.ExternalAddress,
-		CalleeRingtoneURL: calleeRingtoneURL,
+		Token:              token,
+		RoomID:             inv.RoomID,
+		LiveURL:            s.config.RpcConfig.LiveKit.ExternalAddress,
+		BusyLineUserIDList: busyUserIDs,
+		CalleeRingtoneURL:  calleeRingtoneURL,
 	}, nil
 }
 
@@ -178,6 +194,17 @@ func (s *rtcServer) handleInviteInGroup(ctx context.Context, req *rtc.SignalInvi
 	inv.InviterUserID = req.UserID
 	inv.InitiateTime = time.Now().UnixMilli()
 
+	// 检测哪些被叫用户正忙（已在通话中），记录到 BusyLineUserIDList
+	busyUserIDs, err := s.db.GetBusyUserIDs(ctx, inv.InviteeUserIDList)
+	if err != nil {
+		log.ZWarn(ctx, "handleInviteInGroup: GetBusyUserIDs failed (non-fatal)", err)
+	}
+	busySet := make(map[string]struct{}, len(busyUserIDs))
+	for _, uid := range busyUserIDs {
+		busySet[uid] = struct{}{}
+	}
+	inv.BusyLineUserIDList = busyUserIDs
+
 	// 从主叫用户资料获取铃声 URL，注入到邀请信息中，被叫方收到后播放主叫方铃声
 	if inviterInfo, err := s.userClient.GetUserInfo(ctx, req.UserID); err == nil && inviterInfo.CallRingtoneURL != "" {
 		inv.CallerRingtoneURL = inviterInfo.CallRingtoneURL
@@ -227,16 +254,21 @@ func (s *rtcServer) handleInviteInGroup(ctx context.Context, req *rtc.SignalInvi
 			log.ZInfo(ctx, "handleInviteInGroup: skipping invitee (call setting blocked)", "inviteeID", inviteeID)
 			continue
 		}
+		if _, busy := busySet[inviteeID]; busy {
+			log.ZInfo(ctx, "handleInviteInGroup: skip busy invitee", "inviteeID", inviteeID)
+			continue
+		}
 		if err := s.sendSignalingNotification(ctx, req.UserID, inviteeID, int32(constant.ReadGroupChatType), req.OfflinePushInfo, content); err != nil {
 			log.ZWarn(ctx, "sendSignalingNotification to group invitee failed", err, "inviteeID", inviteeID)
 		}
 	}
 
 	return &rtc.SignalInviteInGroupResp{
-		Token:             token,
-		RoomID:            inv.RoomID,
-		LiveURL:           s.config.RpcConfig.LiveKit.ExternalAddress,
-		CalleeRingtoneURL: calleeRingtoneURL,
+		Token:              token,
+		RoomID:             inv.RoomID,
+		LiveURL:            s.config.RpcConfig.LiveKit.ExternalAddress,
+		BusyLineUserIDList: busyUserIDs,
+		CalleeRingtoneURL:  calleeRingtoneURL,
 	}, nil
 }
 
@@ -297,12 +329,12 @@ func (s *rtcServer) handleAccept(ctx context.Context, req *rtc.SignalAcceptReq,
 		log.ZWarn(ctx, "sendSignalingNotification accept to inviter failed", err, "inviterID", dbInv.InviterUserID)
 	}
 
-	// TODO: 群通话可通过 RemoveInvitee 实现精细化状态管理
-	if dbInv.GroupID == "" {
-		if err := s.db.DeleteInvitation(ctx, dbInv.RoomID); err != nil {
-			log.ZWarn(ctx, "handleAccept: DeleteInvitation failed (non-fatal)", err, "roomID", dbInv.RoomID)
-		}
-	}
+	// 接受邀请后不删除 invitation：通话仍在进行，双方应被标记为忙线（BusyLineUserIDList）。
+	// invitation 的清理由以下路径负责：
+	//   - 主动挂断：handleHungUp → DeleteInvitation
+	//   - 主叫取消：handleCancel → DeleteInvitation
+	//   - 被叫拒绝：handleReject → DeleteInvitation / RemoveInvitee
+	//   - 异常中断：MongoDB TTL 索引（expire_at 字段）自动清理
 
 	return &rtc.SignalAcceptResp{
 		Token:   token,
diff --git a/pkg/common/storage/controller/rtc.go b/pkg/common/storage/controller/rtc.go
index 75b5d83f4..8e0e46557 100644
--- a/pkg/common/storage/controller/rtc.go
+++ b/pkg/common/storage/controller/rtc.go
@@ -31,6 +31,8 @@ type RtcDatabase interface {
 	RemoveInvitee(ctx context.Context, roomID string, userID string) error
 	GetInvitationByGroupID(ctx context.Context, groupID string) (*model.SignalInvitation, error)
 	GetInvitationsByRoomIDs(ctx context.Context, roomIDs []string) ([]*model.SignalInvitation, error)
+	// GetBusyUserIDs returns the subset of userIDs that are currently in an active call.
+	GetBusyUserIDs(ctx context.Context, userIDs []string) ([]string, error)
 
 	CreateRecord(ctx context.Context, record *model.SignalRecord) error
 	SearchRecords(ctx context.Context, sendID, recvID string, sessionType int32, startTime, endTime int64, pagination pagination.Pagination) (int64, []*model.SignalRecord, error)
@@ -73,6 +75,10 @@ func (r *rtcDatabase) GetInvitationsByRoomIDs(ctx context.Context, roomIDs []str
 	return r.db.GetInvitationsByRoomIDs(ctx, roomIDs)
 }
 
+func (r *rtcDatabase) GetBusyUserIDs(ctx context.Context, userIDs []string) ([]string, error) {
+	return r.db.GetBusyUserIDs(ctx, userIDs)
+}
+
 func (r *rtcDatabase) CreateRecord(ctx context.Context, record *model.SignalRecord) error {
 	return r.db.CreateRecord(ctx, record)
 }
diff --git a/pkg/common/storage/database/mgo/signal.go b/pkg/common/storage/database/mgo/signal.go
index 4a84b2cc9..0eb7f8b0e 100644
--- a/pkg/common/storage/database/mgo/signal.go
+++ b/pkg/common/storage/database/mgo/signal.go
@@ -117,6 +117,44 @@ func (s *signalMgo) GetInvitationsByRoomIDs(ctx context.Context, roomIDs []strin
 	return mongoutil.Find[*model.SignalInvitation](ctx, s.invColl, bson.M{"room_id": bson.M{"$in": roomIDs}})
 }
 
+func (s *signalMgo) GetBusyUserIDs(ctx context.Context, userIDs []string) ([]string, error) {
+	if len(userIDs) == 0 {
+		return nil, nil
+	}
+	filter := bson.M{
+		"$or": bson.A{
+			bson.M{"inviter_user_id": bson.M{"$in": userIDs}},
+			bson.M{"invitee_user_id_list": bson.M{"$in": userIDs}},
+		},
+	}
+	invitations, err := mongoutil.Find[*model.SignalInvitation](ctx, s.invColl, filter,
+		options.Find().SetProjection(bson.M{"inviter_user_id": 1, "invitee_user_id_list": 1}),
+	)
+	if err != nil {
+		return nil, err
+	}
+	requested := make(map[string]struct{}, len(userIDs))
+	for _, uid := range userIDs {
+		requested[uid] = struct{}{}
+	}
+	busySet := make(map[string]struct{})
+	for _, inv := range invitations {
+		if _, ok := requested[inv.InviterUserID]; ok {
+			busySet[inv.InviterUserID] = struct{}{}
+		}
+		for _, uid := range inv.InviteeUserIDList {
+			if _, ok := requested[uid]; ok {
+				busySet[uid] = struct{}{}
+			}
+		}
+	}
+	busy := make([]string, 0, len(busySet))
+	for uid := range busySet {
+		busy = append(busy, uid)
+	}
+	return busy, nil
+}
+
 func (s *signalMgo) CreateRecord(ctx context.Context, record *model.SignalRecord) error {
 	return mongoutil.InsertMany(ctx, s.recColl, []*model.SignalRecord{record})
 }
diff --git a/pkg/common/storage/database/signal.go b/pkg/common/storage/database/signal.go
index 24b83dcbc..dbc24834b 100644
--- a/pkg/common/storage/database/signal.go
+++ b/pkg/common/storage/database/signal.go
@@ -38,6 +38,9 @@ type SignalDatabase interface {
 	GetInvitationByGroupID(ctx context.Context, groupID string) (*model.SignalInvitation, error)
 	// GetInvitationsByRoomIDs retrieves invitations for the given room IDs.
 	GetInvitationsByRoomIDs(ctx context.Context, roomIDs []string) ([]*model.SignalInvitation, error)
+	// GetBusyUserIDs returns the subset of userIDs that are currently involved in an active call
+	// (either as inviter or as invitee in a pending invitation).
+	GetBusyUserIDs(ctx context.Context, userIDs []string) ([]string, error)
 
 	// CreateRecord stores a completed call record.
 	CreateRecord(ctx context.Context, record *model.SignalRecord) error