diff --git a/internal/application/api/api_application_service.go b/internal/application/api/api_application_service.go
index 04ad165..b9172a1 100644
--- a/internal/application/api/api_application_service.go
+++ b/internal/application/api/api_application_service.go
@@ -20,6 +20,8 @@ import (
 	finance_services "tyapi-server/internal/domains/finance/services"
 	product_entities "tyapi-server/internal/domains/product/entities"
 	product_services "tyapi-server/internal/domains/product/services"
+	subordinate_entities "tyapi-server/internal/domains/subordinate/entities"
+	subordinate_repositories "tyapi-server/internal/domains/subordinate/repositories"
 	user_repositories "tyapi-server/internal/domains/user/repositories"
 	task_entities "tyapi-server/internal/infrastructure/task/entities"
 	"tyapi-server/internal/infrastructure/task/interfaces"
@@ -93,6 +95,7 @@ type ApiApplicationServiceImpl struct {
 	walletService       finance_services.WalletAggregateService
 	subscriptionService *product_services.ProductSubscriptionService
 	balanceAlertService finance_services.BalanceAlertService
+	subordinateRepo     subordinate_repositories.SubordinateRepository
 }
 
 func NewApiApplicationService(
@@ -112,6 +115,7 @@ func NewApiApplicationService(
 	subscriptionService *product_services.ProductSubscriptionService,
 	exportManager *export.ExportManager,
 	balanceAlertService finance_services.BalanceAlertService,
+	subordinateRepo subordinate_repositories.SubordinateRepository,
 ) ApiApplicationService {
 	service := &ApiApplicationServiceImpl{
 		apiCallService:           apiCallService,
@@ -130,6 +134,7 @@ func NewApiApplicationService(
 		walletService:            walletService,
 		subscriptionService:      subscriptionService,
 		balanceAlertService:      balanceAlertService,
+		subordinateRepo:          subordinateRepo,
 	}
 
 	return service
@@ -1108,6 +1113,24 @@ func (s *ApiApplicationServiceImpl) ProcessDeduction(ctx context.Context, cmd *c
 		return err
 	}
 
+	// 优先扣减产品额度（若存在且可用），避免子账号有额度却因钱包余额不足失败
+	deductedByQuota, err := s.tryDeductQuota(ctx, cmd.UserID, cmd.ProductID, cmd.ApiCallID, cmd.TransactionID)
+	if err != nil {
+		s.logger.Error("额度扣减失败",
+			zap.String("transaction_id", cmd.TransactionID),
+			zap.String("user_id", cmd.UserID),
+			zap.String("product_id", cmd.ProductID),
+			zap.Error(err))
+		return err
+	}
+	if deductedByQuota {
+		s.logger.Info("额度扣减成功",
+			zap.String("transaction_id", cmd.TransactionID),
+			zap.String("user_id", cmd.UserID),
+			zap.String("product_id", cmd.ProductID))
+		return nil
+	}
+
 	if err := s.walletService.Deduct(ctx, cmd.UserID, amount, cmd.ApiCallID, cmd.TransactionID, cmd.ProductID); err != nil {
 		s.logger.Error("扣款处理失败",
 			zap.String("transaction_id", cmd.TransactionID),
@@ -1202,6 +1225,25 @@ func (s *ApiApplicationServiceImpl) ProcessCompensation(ctx context.Context, cmd
 
 // validateWalletStatus 验证钱包状态
 func (s *ApiApplicationServiceImpl) validateWalletStatus(ctx context.Context, userID string, product *product_entities.Product, subscription *product_entities.Subscription) error {
+	// 若用户在该产品有可用额度，则本次调用将走额度扣减，不再要求钱包余额预检通过
+	if s.subordinateRepo != nil {
+		quotaAccount, err := s.subordinateRepo.FindQuotaAccount(ctx, userID, product.ID)
+		if err != nil {
+			s.logger.Error("查询额度账户失败",
+				zap.String("user_id", userID),
+				zap.String("product_id", product.ID),
+				zap.Error(err))
+			return ErrSystem
+		}
+		if quotaAccount != nil && quotaAccount.AvailableQuota > 0 {
+			s.logger.Info("额度校验通过，跳过钱包余额预检",
+				zap.String("user_id", userID),
+				zap.String("product_id", product.ID),
+				zap.Int64("available_quota", quotaAccount.AvailableQuota))
+			return nil
+		}
+	}
+
 	// 1. 获取用户钱包信息
 	wallet, err := s.walletService.LoadWalletByUserId(ctx, userID)
 	if err != nil {
@@ -1251,6 +1293,56 @@ func (s *ApiApplicationServiceImpl) validateWalletStatus(ctx context.Context, us
 	return nil
 }
 
+// tryDeductQuota 尝试扣减产品额度；若不存在额度账户则返回 false,nil 以便回退钱包扣款
+func (s *ApiApplicationServiceImpl) tryDeductQuota(ctx context.Context, userID, productID, apiCallID, transactionID string) (bool, error) {
+	if s.subordinateRepo == nil || productID == "" {
+		return false, nil
+	}
+
+	var deducted bool
+	err := s.txManager.ExecuteInTx(ctx, func(txCtx context.Context) error {
+		account, err := s.subordinateRepo.FindQuotaAccount(txCtx, userID, productID)
+		if err != nil {
+			return err
+		}
+		if account == nil {
+			return nil
+		}
+		if account.AvailableQuota <= 0 {
+			return ErrInsufficientBalance
+		}
+
+		before := account.AvailableQuota
+		account.AvailableQuota -= 1
+		account.UsedQuota += 1
+		if err := s.subordinateRepo.UpdateQuotaAccount(txCtx, account); err != nil {
+			return err
+		}
+
+		ledger := &subordinate_entities.UserProductQuotaLedger{
+			UserID:      userID,
+			ProductID:   productID,
+			ChangeType:  subordinate_entities.QuotaLedgerChangeTypeConsumeAPI,
+			DeltaQuota:  -1,
+			BeforeQuota: before,
+			AfterQuota:  account.AvailableQuota,
+			SourceID:    apiCallID,
+			OperatorID:  userID,
+			Remark:      fmt.Sprintf("API调用扣减，transaction_id=%s", transactionID),
+		}
+		if err := s.subordinateRepo.CreateQuotaLedger(txCtx, ledger); err != nil {
+			return err
+		}
+
+		deducted = true
+		return nil
+	})
+	if err != nil {
+		return false, err
+	}
+	return deducted, nil
+}
+
 // validateSubscriptionStatus 验证订阅状态并返回订阅信息
 func (s *ApiApplicationServiceImpl) validateSubscriptionStatus(ctx context.Context, userID string, product *product_entities.Product) (*product_entities.Subscription, error) {
 	// 1. 检查用户是否已订阅该产品
diff --git a/internal/container/container.go b/internal/container/container.go
index 8a2372a..9a48ebd 100644
--- a/internal/container/container.go
+++ b/internal/container/container.go
@@ -811,6 +811,7 @@ func NewContainer() *Container {
 					subscriptionService *product_services.ProductSubscriptionService,
 					exportManager *export.ExportManager,
 					balanceAlertService finance_services.BalanceAlertService,
+					subordinateRepo domain_subordinate_repo.SubordinateRepository,
 				) api_app.ApiApplicationService {
 					return api_app.NewApiApplicationService(
 						apiCallService,
@@ -829,6 +830,7 @@ func NewContainer() *Container {
 						subscriptionService,
 						exportManager,
 						balanceAlertService,
+						subordinateRepo,
 					)
 				},
 				fx.As(new(api_app.ApiApplicationService)),
diff --git a/internal/domains/subordinate/entities/quota.go b/internal/domains/subordinate/entities/quota.go
index fea8ab5..2d713b7 100644
--- a/internal/domains/subordinate/entities/quota.go
+++ b/internal/domains/subordinate/entities/quota.go
@@ -11,6 +11,8 @@ import (
 const (
 	// QuotaLedgerChangeTypePurchaseForSub 主账号为子账号购买额度
 	QuotaLedgerChangeTypePurchaseForSub = "purchase_for_sub"
+	// QuotaLedgerChangeTypeConsumeAPI 用户调用API消耗额度
+	QuotaLedgerChangeTypeConsumeAPI = "api_consume"
 )
 
 // SubordinateQuotaPurchase 主账号为子账号购买额度记录