diff --git a/internal/service/commission_calculation/service.go b/internal/service/commission_calculation/service.go
index 211250d..8f9c28e 100644
--- a/internal/service/commission_calculation/service.go
+++ b/internal/service/commission_calculation/service.go
@@ -141,7 +141,14 @@ func (s *Service) CalculateCostDiffCommission(ctx context.Context, order *model.
 		return nil, errors.Wrap(errors.CodeDatabaseError, err, "获取销售店铺失败")
 	}
 
-	sellerProfit := order.TotalAmount - order.SellerCostPrice
+	// 卖家利润 = 实际收款 - 成本价，必须用 ActualPaidAmount 而非 TotalAmount
+	// TotalAmount 在 fix-order-price-semantics 后始终存零售价，代理自购时会错误产生佣金
+	var sellerProfit int64
+	if order.ActualPaidAmount != nil {
+		sellerProfit = *order.ActualPaidAmount - order.SellerCostPrice
+	} else {
+		sellerProfit = order.TotalAmount - order.SellerCostPrice
+	}
 	if sellerProfit > 0 {
 		records = append(records, &model.CommissionRecord{
 			BaseModel: model.BaseModel{