diff --git a/YLErpWeb/Views/SwapTrade2/SwapUnwind.cshtml b/YLErpWeb/Views/SwapTrade2/SwapUnwind.cshtml
index c1fdaf8d..353c255e 100644
--- a/YLErpWeb/Views/SwapTrade2/SwapUnwind.cshtml
+++ b/YLErpWeb/Views/SwapTrade2/SwapUnwind.cshtml
@@ -27,6 +27,7 @@
     <script src="~/Scripts/app/swaptrade/swapPricePrecisionHelper.js?v=@HtmlUtil.JsVersion"></script>
     <script src="~/Scripts/app/swaptrade/swapCalc.js?v=@HtmlUtil.JsVersion"></script>
     <script src="~/Scripts/app/swaptrade/unwindBondCalc.js?v=@HtmlUtil.JsVersion"></script>
+    <script src="~/Scripts/app/swaptrade/unwindLegSign.js?v=@HtmlUtil.JsVersion"></script>
     <script src="~/Scripts/app/swaptrade/unwindSwapTrade.js?v=@HtmlUtil.JsVersion"></script>
 }
 <div class="pb-3" id="vueDiv">
diff --git a/YLErpWeb/fe-tests/closePercentInterestRefresh.test.js b/YLErpWeb/fe-tests/closePercentInterestRefresh.test.js
index 2fb4a7eb..5d31102f 100644
--- a/YLErpWeb/fe-tests/closePercentInterestRefresh.test.js
+++ b/YLErpWeb/fe-tests/closePercentInterestRefresh.test.js
@@ -155,6 +155,8 @@ function loadVueApp(model, mockPost) {
             roundExitYtm(v) { return v; },
             applyManualEdit(s) { return s; }
         },
+        // 收付方向符号：纯函数零依赖，直接喂真实模块（映射冻结由 unwindLegSign.test.js 覆盖）
+        UnwindLegSign: require('../wwwroot/Scripts/app/swaptrade/unwindLegSign.js'),
         _: {
             round(value, precision) {
                 return Number(Number(value || 0).toFixed(precision || 0));
diff --git a/YLErpWeb/fe-tests/unwindLegSign.test.js b/YLErpWeb/fe-tests/unwindLegSign.test.js
new file mode 100644
index 00000000..3258511c
--- /dev/null
+++ b/YLErpWeb/fe-tests/unwindLegSign.test.js
@@ -0,0 +1,47 @@
+/**
+ * unwindLegSign.test.js — 平仓页收付方向符号映射（隐式约定显式化）
+ * ============================================================================
+ * 冻结的领域事实（2026-08-21 业务确认）：
+ *   利息腿（融资成本）与保证金腿（返息/返还本金）方向【必须相反】——
+ *   利息是买方持有标的向交易商融资的成本（买方付出去的钱）；
+ *   保证金是客户自己交的抵押金，返息/返还是把客户自己的钱退回来。
+ *   两者对同一 InterestDirection 枚举符号互为镜像，这是业务事实而非笔误，
+ *   任何人"顺手统一"这两个符号都会翻转保证金返还方向（资损级 bug）。
+ *
+ * 另冻结：PayDirection==1 → +1、PositionType==1(多头) → +1 的浮动端/多空符号。
+ *
+ * 运行：cd YLErpWeb/fe-tests && npx jest unwindLegSign
+ */
+const UnwindLegSign = require('../wwwroot/Scripts/app/swaptrade/unwindLegSign.js');
+
+describe('收付方向符号：各枚举映射', () => {
+    test('利息盈亏（利息腿/保证金腿通用）：收取(1)→+1，支付(其他)→-1', () => {
+        expect(UnwindLegSign.interestPnlSign(1)).toBe(1);
+        expect(UnwindLegSign.interestPnlSign(0)).toBe(-1);
+        expect(UnwindLegSign.interestPnlSign(null)).toBe(-1);
+    });
+
+    test('保证金腿返还本金：与利息腿同枚举反号（返的是客户自己的钱）', () => {
+        expect(UnwindLegSign.marginRebatePrincipalSign(1)).toBe(-1);
+        expect(UnwindLegSign.marginRebatePrincipalSign(0)).toBe(1);
+        expect(UnwindLegSign.marginRebatePrincipalSign(null)).toBe(1);
+    });
+
+    test('浮动端收付：PayDirection==1(收取)→+1；多空：PositionType==1(多头)→+1', () => {
+        expect(UnwindLegSign.payDirectionSign(1)).toBe(1);
+        expect(UnwindLegSign.payDirectionSign(0)).toBe(-1);
+        expect(UnwindLegSign.positionTypeSign(1)).toBe(1);
+        expect(UnwindLegSign.positionTypeSign(0)).toBe(-1);
+    });
+});
+
+describe('不变量：利息腿与保证金腿符号互为镜像（业务事实，禁止统一）', () => {
+    test('同一 InterestDirection 下两符号之和恒为 0', () => {
+        [1, 0, null, undefined, 2].forEach(dir => {
+            expect(
+                UnwindLegSign.interestPnlSign(dir)
+                + UnwindLegSign.marginRebatePrincipalSign(dir)
+            ).toBe(0);
+        });
+    });
+});
diff --git a/YLErpWeb/fe-tests/unwindSwapTrade.test.js b/YLErpWeb/fe-tests/unwindSwapTrade.test.js
index f0774f96..488a0c3b 100644
--- a/YLErpWeb/fe-tests/unwindSwapTrade.test.js
+++ b/YLErpWeb/fe-tests/unwindSwapTrade.test.js
@@ -66,6 +66,8 @@ function loadUnwindHelpers() {
             roundHalfAwayFromZero(value) { return value; },
             calcCloseQtyByOriginalPercent() { return 0; }
         },
+        // 收付方向符号：纯函数零依赖，直接喂真实模块（映射冻结由 unwindLegSign.test.js 覆盖）
+        UnwindLegSign: require('../wwwroot/Scripts/app/swaptrade/unwindLegSign.js'),
         _: {
             round(value, precision) {
                 return Number(Number(value || 0).toFixed(precision || 0));
diff --git a/YLErpWeb/wwwroot/Scripts/app/swaptrade/unwindLegSign.js b/YLErpWeb/wwwroot/Scripts/app/swaptrade/unwindLegSign.js
new file mode 100644
index 00000000..a07d62cd
--- /dev/null
+++ b/YLErpWeb/wwwroot/Scripts/app/swaptrade/unwindLegSign.js
@@ -0,0 +1,45 @@
+/**
+ * unwindLegSign.js — 平仓页收付方向符号（纯函数）
+ * ============================================================================
+ * 把散落在 unwindSwapTrade.js 各计算式里的裸三元（xxx==1 ? ±1 : ∓1）显式化为命名函数。
+ * 【为什么必须显式化】利息盈亏与保证金返还本金对同一 InterestDirection 枚举符号相反——
+ * 这是业务事实而非笔误，任何"顺手统一"都会翻转保证金返还方向（资损级 bug）：
+ *   利息盈亏（利息腿/保证金腿通用，changeInterestAmount 对两类行都生效）：
+ *           收益互换中买方为持有标的向交易商融资，利息=融资成本（买方付出去的钱），
+ *           InterestDirection==1(收取) → 盈亏记 +1；
+ *   保证金返还本金：保证金是客户自己交的抵押金，返息/返还本金是把客户自己的钱退回来，
+ *           本金流方向与利息（成本）相反 → 同枚举符号取镜像 -1。
+ *
+ * 其余两个符号：PayDirection==1(浮动端收取) → +1；PositionType==1(多头) → +1。
+ *
+ * 加载：浏览器 script 标签（先于 unwindSwapTrade.js）；Node：module.exports 供 jest。
+ */
+var UnwindLegSign = (function () {
+    'use strict';
+
+    // Number()===1 与页面原 ==1 对 '1'/true/数字等实际入参等价，且对 null/undefined 同样落到 -1 分支
+    function interestPnlSign(interestDirection) {
+        return Number(interestDirection) === 1 ? 1 : -1;
+    }
+
+    function marginRebatePrincipalSign(interestDirection) {
+        return Number(interestDirection) === 1 ? -1 : 1;
+    }
+
+    function payDirectionSign(payDirection) {
+        return Number(payDirection) === 1 ? 1 : -1;
+    }
+
+    function positionTypeSign(positionType) {
+        return Number(positionType) === 1 ? 1 : -1;
+    }
+
+    return Object.freeze({
+        interestPnlSign: interestPnlSign,
+        marginRebatePrincipalSign: marginRebatePrincipalSign,
+        payDirectionSign: payDirectionSign,
+        positionTypeSign: positionTypeSign
+    });
+}());
+
+if (typeof module === 'object' && module.exports) module.exports = UnwindLegSign;
diff --git a/YLErpWeb/wwwroot/Scripts/app/swaptrade/unwindSwapTrade.js b/YLErpWeb/wwwroot/Scripts/app/swaptrade/unwindSwapTrade.js
index 764e9623..40b5da7c 100644
--- a/YLErpWeb/wwwroot/Scripts/app/swaptrade/unwindSwapTrade.js
+++ b/YLErpWeb/wwwroot/Scripts/app/swaptrade/unwindSwapTrade.js
@@ -69,8 +69,6 @@ const vue = new Vue({
         // 平仓比例展示/输入均为"占期初(original)"语义(A)：默认与每次重开都基于原始名义本金。
         // oriClosePercent = 剩余名义本金/期初名义本金 = 最多可平比例（不能平超过剩余持仓）。
         oriClosePercent: 1,
-        ratio: 1,
-        shortRatio: 1,
     },
     computed: {
         maxUnwindDate() {
@@ -125,8 +123,6 @@ const vue = new Vue({
             this.marginList = model.FlowEvents.filter((item) => {
                 return item.InterestMode == 5 || item.InterestMode == 6;
             });
-            this.ratio = this.floatPosition.PayDirection == 1 ? -1 : 1;
-            this.shortRatio = this.floatPosition.PositionType == 1 ? 1 : -1;
             this.TradeStartDate = model.TradeStartDate;
             // 最多可平比例(占期初口径) = 剩余名义本金 / 期初名义本金；分母为 0 时兜底为 1
             this.oriClosePercent = (this.deal.NotionalValue && this.deal.PosiNotionalValue)
@@ -424,8 +420,8 @@ const vue = new Vue({
         },
         calcFloatClosePnl() {//计算浮动端平仓盈亏
             var thisObj = this;
-            let floatRatio = thisObj.floatPosition.PayDirection == 1 ? 1 : -1;
-            let longRatio = thisObj.floatPosition.PositionType == 1 ? 1 : -1;
+            let floatRatio = UnwindLegSign.payDirectionSign(thisObj.floatPosition.PayDirection);
+            let longRatio = UnwindLegSign.positionTypeSign(thisObj.floatPosition.PositionType);
             let TradingFee = thisObj.floatPosition.TradingFee == "" ? 0 : parseFloat(thisObj.floatPosition.TradingFee);
             let TradingFeePending = thisObj.floatPosition.TradingFeePending == "" ? 0 : parseFloat(thisObj.floatPosition.TradingFeePending);
             let deliveryPrice = thisObj.getStorageDeliveryPrice();
@@ -440,7 +436,7 @@ const vue = new Vue({
             this.calcFloatClosePnl();
         },
         changeInterestAmount(item) {//修改利息金额
-            let interestRatio = item.InterestDirection == 1 ? 1 : -1;
+            let interestRatio = UnwindLegSign.interestPnlSign(item.InterestDirection);
             item.InterestClosePnL = formatSwapAmount(parseFloat(item.InterestAmount) * interestRatio + parseFloat(item.InterestFee) * interestRatio);
             this.calcCloseAmount();
         },
@@ -450,8 +446,8 @@ const vue = new Vue({
         //    this.calcCloseAmount();
         //},
         calcCloseAmount() {//计算平仓总额=浮动收取+利息收取-浮动支付-利息支付
-            let floatRatio = this.floatPosition.PayDirection == 1 ? 1 : -1;
-            let ratio = this.floatPosition.PositionType == 1 ? 1 : -1;
+            let floatRatio = UnwindLegSign.payDirectionSign(this.floatPosition.PayDirection);
+            let ratio = UnwindLegSign.positionTypeSign(this.floatPosition.PositionType);
             let thisObj = this;
             let pnl = parseFloat(this.floatPosition.FloatPnlSum);
             let TradingFee = thisObj.floatPosition.TradingFee == "" ? 0 : parseFloat(thisObj.floatPosition.TradingFee);
@@ -468,14 +464,14 @@ const vue = new Vue({
                 thisObj.floatPosition.TradingAmountFeeAvg = deliveryPrice + (TradingFee / thisObj.deal.CloseQty) * ratio;
             }
             this.interestList.forEach(x => {
-                /*let interestRatio = x.InterestDirection == 1 ? 1 : -1;*/
                 let interestAmount = parseFloat(x.InterestClosePnL);
                 thisObj.deal.SwapCloseAmount = parseFloat(thisObj.deal.SwapCloseAmount) + interestAmount;
                 thisObj.deal.SwapRealizedPnL = parseFloat(thisObj.deal.SwapRealizedPnL) + interestAmount;
             });
             this.marginList.forEach(x => {
                 let interestAmount = parseFloat(x.InterestClosePnL);
-                let interestRatio = x.InterestDirection == 1 ? -1 : 1;
+                // 保证金返还本金符号与利息盈亏同枚举反号（见 unwindLegSign.js 头注——业务事实勿统一）
+                let interestRatio = UnwindLegSign.marginRebatePrincipalSign(x.InterestDirection);
                 thisObj.deal.SwapCloseAmount = parseFloat(thisObj.deal.SwapCloseAmount) + interestAmount;
                 thisObj.deal.SwapMarginRebatePnl = parseFloat(thisObj.deal.SwapMarginRebatePnl) + interestAmount;
                 thisObj.deal.SwapRealizedPnL = parseFloat(thisObj.deal.SwapRealizedPnL) + interestAmount;