diff --git a/internal/application/api/api_application_service.go b/internal/application/api/api_application_service.go
index 370bacc..b710429 100644
--- a/internal/application/api/api_application_service.go
+++ b/internal/application/api/api_application_service.go
@@ -310,7 +310,7 @@ func (s *ApiApplicationServiceImpl) validateApiCall(ctx context.Context, cmd *co
 			s.logger.Warn("子账号主账号AccessId校验失败：未找到主从关系",
 				zap.String("user_id", apiUser.UserId),
 				zap.String("parent_access_id", parentAccessID))
-			return nil, ErrQueryFailed
+			return nil, ErrSubordinateLinkNotFound
 		}
 
 		parentApiUser, err := s.apiUserService.LoadApiUserByUserId(ctx, link.ParentUserID)
@@ -326,7 +326,7 @@ func (s *ApiApplicationServiceImpl) validateApiCall(ctx context.Context, cmd *co
 				zap.String("child_user_id", apiUser.UserId),
 				zap.String("parent_user_id", link.ParentUserID),
 				zap.String("parent_access_id", parentAccessID))
-			return nil, ErrQueryFailed
+			return nil, ErrSubordinateParentMismatch
 		}
 	}
 	result.SetRequestParams(paramsMap)
diff --git a/internal/application/api/errors.go b/internal/application/api/errors.go
index 3e16f96..68ca8b4 100644
--- a/internal/application/api/errors.go
+++ b/internal/application/api/errors.go
@@ -22,7 +22,9 @@ var (
 	ErrProductNotSubscribed = errors.New("未订阅此产品")
 	ErrSubscriptionExpired  = errors.New("订阅已过期")
 	ErrSubscriptionSuspended = errors.New("订阅已暂停")
-	ErrBusiness             = errors.New("业务失败")
+	ErrBusiness                      = errors.New("业务失败")
+	ErrSubordinateLinkNotFound       = errors.New("非子账号，无法使用master_accessid")
+	ErrSubordinateParentMismatch     = errors.New("master_accessid与主账号不匹配")
 )
 
 // 错误码映射 - 严格按照用户要求
@@ -45,7 +47,9 @@ var ErrorCodeMap = map[error]int{
 	ErrProductNotSubscribed: 1008,
 	ErrSubscriptionExpired:  1008,
 	ErrSubscriptionSuspended: 1008,
-	ErrBusiness:             2001,
+	ErrBusiness:                      2001,
+	ErrSubordinateLinkNotFound:       1301,
+	ErrSubordinateParentMismatch:     1302,
 }
 
 // GetErrorCode 获取错误对应的错误码
diff --git a/internal/application/subordinate/dto/commands/subordinate_commands.go b/internal/application/subordinate/dto/commands/subordinate_commands.go
index 83888a0..02d7d4e 100644
--- a/internal/application/subordinate/dto/commands/subordinate_commands.go
+++ b/internal/application/subordinate/dto/commands/subordinate_commands.go
@@ -12,7 +12,7 @@ type SubPortalRegisterCommand struct {
 // CreateInvitationCommand 主账号创建邀请
 type CreateInvitationCommand struct {
 	ParentUserID string
-	// ExpiresInHours 可选，0 用默认 168 小时
+	// ExpiresInHours 可选，0 或不传为永久有效（100年）
 	ExpiresInHours int `json:"expires_in_hours"`
 }
 
diff --git a/internal/application/subordinate/subordinate_application_service_impl.go b/internal/application/subordinate/subordinate_application_service_impl.go
index dc5d07d..62050f8 100644
--- a/internal/application/subordinate/subordinate_application_service_impl.go
+++ b/internal/application/subordinate/subordinate_application_service_impl.go
@@ -127,7 +127,8 @@ func (s *SubordinateApplicationServiceImpl) RegisterSubPortal(ctx context.Contex
 func (s *SubordinateApplicationServiceImpl) CreateInvitation(ctx context.Context, cmd *commands.CreateInvitationCommand) (*responses.CreateInvitationResponse, error) {
 	hours := cmd.ExpiresInHours
 	if hours <= 0 {
-		hours = 24 * 7
+		// 永久有效：设置100年后过期
+		hours = 24 * 365 * 100
 	}
 	raw, hash, err := GenerateInviteToken()
 	if err != nil {