diff --git a/internal/api/delete_user.go b/internal/api/delete_user.go
index 81c87103f..ccc3be175 100644
--- a/internal/api/delete_user.go
+++ b/internal/api/delete_user.go
@@ -18,6 +18,7 @@ import (
 // It follows the same direct-DB pattern as UserGlobalBlackApi.
 type DeleteUserApi struct {
 	userDB         database.User
+	phoneSNDB      database.PhoneSN
 	authClient     *rpcli.AuthClient
 	groupClient    group.GroupClient
 	friendClient   relation.FriendClient
@@ -26,6 +27,7 @@ type DeleteUserApi struct {
 
 func NewDeleteUserApi(
 	userDB database.User,
+	phoneSNDB database.PhoneSN,
 	authClient *rpcli.AuthClient,
 	groupClient group.GroupClient,
 	friendClient relation.FriendClient,
@@ -33,6 +35,7 @@ func NewDeleteUserApi(
 ) *DeleteUserApi {
 	return &DeleteUserApi{
 		userDB:         userDB,
+		phoneSNDB:      phoneSNDB,
 		authClient:     authClient,
 		groupClient:    groupClient,
 		friendClient:   friendClient,
@@ -131,7 +134,14 @@ func (d *DeleteUserApi) DeleteUser(c *gin.Context) {
 		pageNumber++
 	}
 
-	// 5. Hard-delete user document from MongoDB.
+	// 5. Delete phone_sn_info record bound to this user's phone number.
+	if phone := users[0].Phone; phone != "" {
+		if err := d.phoneSNDB.DeleteByPhone(c, phone); err != nil {
+			log.ZWarn(c, "DeleteUser: DeleteByPhone failed", err, "userID", req.UserID, "phone", phone)
+		}
+	}
+
+	// 6. Hard-delete user document from MongoDB.
 	// Redis cache will become stale and expire via TTL; the user can no longer
 	// authenticate because their tokens were already invalidated in step 2.
 	if err := d.userDB.Delete(c, []string{req.UserID}); err != nil {
diff --git a/internal/api/router.go b/internal/api/router.go
index bbfed0eba..9f622be9e 100644
--- a/internal/api/router.go
+++ b/internal/api/router.go
@@ -137,7 +137,7 @@ func newGinRouter(ctx context.Context, client discovery.SvcDiscoveryRegistry, co
 	m := NewMessageApi(msg.NewMsgClient(msgConn), rpcli.NewUserClient(userConn), config.Share.IMAdminUserID)
 	cp := NewCaptchaApi(pbcaptcha.NewCaptchaClient(captchaConn))
 	bl := NewUserGlobalBlackApi(blacklistCtrl, userDB, config.Share.IMAdminUserID, rpcli.NewAuthClient(authConn))
-	du := NewDeleteUserApi(userDB, rpcli.NewAuthClient(authConn), group.NewGroupClient(groupConn), relation.NewFriendClient(friendConn), config.Share.IMAdminUserID)
+	du := NewDeleteUserApi(userDB, phoneSNDB, rpcli.NewAuthClient(authConn), group.NewGroupClient(groupConn), relation.NewFriendClient(friendConn), config.Share.IMAdminUserID)
 	phoneSN := NewPhoneSNApi(phoneSNDB)
 	userRouterGroup := r.Group("/user")
 	{
diff --git a/pkg/common/storage/database/mgo/phone_sn.go b/pkg/common/storage/database/mgo/phone_sn.go
index fa09f3657..594ea72dc 100644
--- a/pkg/common/storage/database/mgo/phone_sn.go
+++ b/pkg/common/storage/database/mgo/phone_sn.go
@@ -48,6 +48,14 @@ func (p *phoneSNMgo) GetByPhone(ctx context.Context, phone string) (*model.Phone
 	return doc, nil
 }
 
+func (p *phoneSNMgo) DeleteByPhone(ctx context.Context, phone string) error {
+	if phone == "" {
+		return nil
+	}
+	_, err := p.coll.DeleteOne(ctx, bson.M{"phone": phone})
+	return errs.Wrap(err)
+}
+
 func (p *phoneSNMgo) Upsert(ctx context.Context, phone string, userID int64, isSnd bool) error {
 	if phone == "" {
 		return errs.ErrArgs.WrapMsg("phone is empty")
diff --git a/pkg/common/storage/database/phone_sn.go b/pkg/common/storage/database/phone_sn.go
index 3ded66b0f..055a6c5b5 100644
--- a/pkg/common/storage/database/phone_sn.go
+++ b/pkg/common/storage/database/phone_sn.go
@@ -17,4 +17,6 @@ type PhoneSN interface {
 	GetByPhone(ctx context.Context, phone string) (*model.PhoneSNInfo, error)
 	// Upsert 写入或更新 is_snd 与 user_id
 	Upsert(ctx context.Context, phone string, userID int64, isSnd bool) error
+	// DeleteByPhone 按手机号删除记录；记录不存在时不报错
+	DeleteByPhone(ctx context.Context, phone string) error
 }