diff --git a/UnitTestProject/Modules/SwapModule/SwapIncomeScenarioTest.cs b/UnitTestProject/Modules/SwapModule/SwapIncomeScenarioTest.cs
index 5a1d4308..02aaf36d 100644
--- a/UnitTestProject/Modules/SwapModule/SwapIncomeScenarioTest.cs
+++ b/UnitTestProject/Modules/SwapModule/SwapIncomeScenarioTest.cs
@@ -63,5 +63,35 @@ namespace YLErp.Modules.SwapModule
             Assert.AreEqual(ClientCashInCashOut.系统操作_预付金返息, service.ClientCashCalls[1].action);
             Console.WriteLine($"SI_002: 互换={service.ClientCashCalls[0].amount}, 预付金返息={service.ClientCashCalls[1].amount} ✅");
         }
+
+        [TestMethod]
+        public void SI_003_SwapIncome_含预付金腿_不返还预付金本金()
+        {
+            var td = SwapDealTestFactory.CreateTrade();
+            td.ExerciseDate = new DateTime(2026, 12, 31);
+            var service = new TestableSwapDealService(td);
+            var unwindData = SwapDealTestFactory.CreateUnwindData(swapRealizedPnL: 0m);
+            unwindData.FlowEvents.Add(new swap_flow_event
+            {
+                UnderlyingCode = "UT-FLOAT",
+                MarkClosePnl = 100m,
+                PayDirection = 1
+            });
+            unwindData.FlowEvents.Add(new swap_flow_event
+            {
+                InterestMode = (int)InterestModeEnum.初始预付金,
+                InterestDirection = 1,
+                InterestPrincipal = 10000m,
+                InterestClosePnL = 2m
+            });
+
+            service.SwapIncome(unwindData);
+
+            Assert.AreEqual(0m, unwindData.SwapMarginAmount, "手动互换不应返还预付金本金");
+            Assert.IsFalse(service.ClientCashCalls.Any(x => x.action == ClientCashInCashOut.系统操作_应付预付金),
+                "手动互换不应生成应付预付金流水");
+            Assert.IsTrue(service.ClientCashCalls.Any(x => x.action == ClientCashInCashOut.系统操作_预付金返息),
+                "手动互换仍应结算预付金返息");
+        }
     }
 }
diff --git a/UnitTestProject/Modules/SwapModule/SwapUnwindScenarioTest.cs b/UnitTestProject/Modules/SwapModule/SwapUnwindScenarioTest.cs
index 96b14d5f..e156f2b9 100644
--- a/UnitTestProject/Modules/SwapModule/SwapUnwindScenarioTest.cs
+++ b/UnitTestProject/Modules/SwapModule/SwapUnwindScenarioTest.cs
@@ -166,6 +166,35 @@ namespace YLErp.Modules.SwapModule
             Console.WriteLine($"UW_005: 反序列化SwapRealizedPnL=8000, 资金流水={service.ClientCashCalls[0].amount}, TradeStatus={td.TradeStatus} ✅");
         }
 
+        [TestMethod]
+        public void UW_005A_ApproveSwapTrade_互换审核_不返还预付金本金()
+        {
+            var td = SwapDealTestFactory.CreateTrade();
+            td.ExerciseDate = new DateTime(2026, 12, 31);
+            var unwindData = SwapDealTestFactory.CreateUnwindData(
+                swapRealizedPnL: 100m, swapMarginAmount: -10000m);
+            var swapEvent = new swap_event
+            {
+                id = 2,
+                SwapTradeId = SwapDealTestFactory.SwapTradeId,
+                EventType = (int)SwapEventTypeEnum.互换,
+                Invalid = false,
+                EventData = JsonConvert.SerializeObject(unwindData)
+            };
+            var service = new TestableSwapDealService(td,
+                swapEvents: new Dictionary<int, swap_event>
+                {
+                    [(int)SwapEventTypeEnum.互换] = swapEvent
+                });
+
+            service.ApproveSwapTrade(td, (int)SwapEventTypeEnum.互换);
+
+            Assert.AreEqual(1, service.ClientCashCalls.Count, "互换审批只应生成互换结算流水");
+            Assert.AreEqual(ClientCashInCashOut.系统操作_互换, service.ClientCashCalls[0].action);
+            Assert.IsFalse(service.ClientCashCalls.Any(x => x.action == ClientCashInCashOut.系统操作_应付预付金),
+                "互换审批不应生成应付预付金流水");
+        }
+
         // ================================================================
         // 场景6：ApplySwapTrade 提交审核 —— 前置校验与保存事件
         // ================================================================
diff --git a/YLErpDAL/Modules/SwapModule/SwapDealService.cs b/YLErpDAL/Modules/SwapModule/SwapDealService.cs
index 6bb9a47b..cb07edae 100644
--- a/YLErpDAL/Modules/SwapModule/SwapDealService.cs
+++ b/YLErpDAL/Modules/SwapModule/SwapDealService.cs
@@ -144,6 +144,10 @@ namespace YLErp.Modules.SwapModule
             if (unwindData.FlowEvents.Any(x => !string.IsNullOrEmpty(x.UnderlyingCode)))
             {
                 CalcCloseAmount(unwindData);
+                if (eventType == (int)SwapEventTypeEnum.互换)
+                {
+                    unwindData.SwapMarginAmount = 0;
+                }
                 return;
             }
 
@@ -2013,7 +2017,7 @@ namespace YLErp.Modules.SwapModule
             }
             string action = eventType == (int)SwapEventTypeEnum.互换 ? ClientCashInCashOut.系统操作_互换 : ClientCashInCashOut.系统操作_平仓费;
             int clientCashId = AddClientCash(td, Convert.ToDouble(-swapEvent.unwindData.SwapRealizedPnL), action, swapEvent.unwindData.ValueDate);
-            if (swapEvent.unwindData.SwapMarginAmount != 0)
+            if (eventType == (int)SwapEventTypeEnum.平仓 && swapEvent.unwindData.SwapMarginAmount != 0)
             {
                 AddClientCash(td, Convert.ToDouble(swapEvent.unwindData.SwapMarginAmount), ClientCashInCashOut.系统操作_应付预付金, swapEvent.unwindData.ValueDate);
             }