diff --git a/pages/apply/apply.js b/pages/apply/apply.js
index 9893981..55f57ed 100644
--- a/pages/apply/apply.js
+++ b/pages/apply/apply.js
@@ -216,6 +216,9 @@ Page({
     projectGroups: [],   // 分组后的展示数据
     couponCode: '',
     totalPrice: 0,
+    originalPrice: 0,
+    discountPrice: 0,
+    usedCouponId: null,
     submitting: false,
     openidLoading: false,
     myAuth: null
@@ -503,7 +506,12 @@ Page({
   _recalcAmountNow() {
     const items = buildCalculateAmountItems(this.data.projectGroups);
     if (!items.length) {
-      this.setData({ totalPrice: 0 });
+      this.setData({ 
+        totalPrice: 0,
+        originalPrice: 0,
+        discountPrice: 0,
+        usedCouponId: null
+      });
       return;
     }
 
@@ -514,34 +522,58 @@ Page({
       needAuth: true,
       data: {
         eventId: Number(this.data.eventId),
-        registrationMode: 2,
+        registrationMode: 1,
         items
       },
       contentType: 'application/json'
     })
       .then((res) => {
-        // 兼容：后端可能返回 number / string / {amount}
         if (seq !== this._calcSeq) return;
-        let amount = null;
-        if (typeof res === 'number') amount = res;
-        else if (typeof res === 'string') {
+        
+        let totalAmount = null;
+        let originalPrice = 0;
+        let discountPrice = 0;
+        
+        if (typeof res === 'number') {
+          totalAmount = res;
+          originalPrice = res;
+        } else if (typeof res === 'string') {
           const n = Number(res);
-          amount = Number.isNaN(n) ? null : n;
+          totalAmount = Number.isNaN(n) ? null : n;
+          originalPrice = totalAmount || 0;
         } else if (res && typeof res === 'object') {
-          const v = res.amount != null ? res.amount : res.payAmount != null ? res.payAmount : res.totalAmount;
-          const n = Number(v);
-          amount = Number.isNaN(n) ? null : n;
+          // 从统一的 CalculateAmountOutput 中获取数据
+          totalAmount = res.totalAmount != null ? Number(res.totalAmount) : 
+                        (res.amount != null ? Number(res.amount) : 
+                        (res.payAmount != null ? Number(res.payAmount) : null));
+          originalPrice = res.originalAmount != null ? Number(res.originalAmount) : totalAmount || 0;
+          discountPrice = res.discountAmount != null ? Number(res.discountAmount) : 0;
         }
-        if (amount == null) {
+        
+        if (totalAmount == null) {
           // fallback：仍然展示前端计算的费用，避免空白
-          this.setData({ totalPrice: calcTotalPrice(this.data.projectGroups) });
+          const fallbackPrice = calcTotalPrice(this.data.projectGroups);
+          this.setData({ 
+            totalPrice: fallbackPrice,
+            originalPrice: fallbackPrice,
+            discountPrice: 0
+          });
         } else {
-          this.setData({ totalPrice: amount });
+          this.setData({ 
+            totalPrice: totalAmount,
+            originalPrice: originalPrice || totalAmount,
+            discountPrice: discountPrice || 0
+          });
         }
       })
       .catch(() => {
         if (seq !== this._calcSeq) return;
-        this.setData({ totalPrice: calcTotalPrice(this.data.projectGroups) });
+        const fallbackPrice = calcTotalPrice(this.data.projectGroups);
+        this.setData({ 
+          totalPrice: fallbackPrice,
+          originalPrice: fallbackPrice,
+          discountPrice: 0
+        });
       });
   },
 
@@ -549,6 +581,51 @@ Page({
     this.setData({ couponCode: (e.detail.value || '').trim() });
   },
 
+  /**
+   * 验证并应用优惠券
+   */
+  async onValidateCoupon() {
+    const couponCode = this.data.couponCode;
+    if (!couponCode) {
+      wx.showToast({ title: '请输入优惠券兑换码', icon: 'none' });
+      return;
+    }
+
+    wx.showLoading({ title: '验证中', mask: true });
+    try {
+      const res = await request({
+        path: API.couponValidate,
+        method: 'POST',
+        needAuth: true,
+        data: {
+          eventId: Number(this.data.eventId),
+          couponCode: couponCode,
+          originalAmount: this.data.originalPrice || this.data.totalPrice
+        },
+        contentType: 'application/json'
+      });
+
+      if (res && res.isValid) {
+        this.setData({
+          usedCouponId: res.couponId,
+          totalPrice: res.finalAmount,
+          discountPrice: res.discountAmount || 0,
+          originalPrice: res.originalAmount || this.data.originalPrice
+        });
+        wx.showToast({ title: '优惠券应用成功', icon: 'success' });
+      } else {
+        wx.showToast({ title: res.invalidReason || '优惠券无效', icon: 'none' });
+      }
+    } catch (error) {
+      wx.showToast({ 
+        title: error && error.message ? error.message : '验证失败，请稍后重试', 
+        icon: 'none' 
+      });
+    } finally {
+      wx.hideLoading();
+    }
+  },
+
   /** 收集已选的 projectId + groupId */
   _getSelectedItems() {
     const items = [];
@@ -717,12 +794,16 @@ Page({
   },
 
   /** 获取支付信息 */
-  _getPaymentInfo(registrationId, openId) {
+  _getPaymentInfo(registrationId, openid) {
     return request({
       path: '/api/eventclient/payment-info',
       method: 'POST',
       needAuth: true,
-      data: { registrationId, openId },
+      data: { 
+        registrationId, 
+        openId: openid,
+        couponId: this.data.usedCouponId
+      },
       contentType: 'application/json'
     });
   },
diff --git a/pages/apply/apply.wxml b/pages/apply/apply.wxml
index 8160529..a5706f9 100644
--- a/pages/apply/apply.wxml
+++ b/pages/apply/apply.wxml
@@ -29,10 +29,25 @@
       <!-- 优惠券 -->
       <view class="coupon-row">
         <input class="coupon-input" placeholder="请输入优惠卷兑换码" placeholder-class="coupon-placeholder" value="{{couponCode}}" bindinput="onCouponInput" />
-        <view class="coupon-icon">
-          <text class="coupon-icon-text">⊙</text>
+        <button class="coupon-btn" bindtap="onValidateCoupon">验证</button>
+      </view>
+      
+      <!-- 金额显示 -->
+      <view class="price-section">
+        <view wx:if="{{discountPrice > 0}}" class="price-row">
+          <text class="price-label">原价：</text>
+          <text class="original-price">¥{{originalPrice}}</text>
+        </view>
+        <view wx:if="{{discountPrice > 0}}" class="price-row">
+          <text class="price-label">优惠：</text>
+          <text class="discount-price">-¥{{discountPrice}}</text>
+        </view>
+        <view class="price-row total">
+          <text class="price-label">合计：</text>
+          <text class="total-price">¥{{totalPrice}}</text>
         </view>
       </view>
+      
       <!-- 底部占位，避免被 bottom-bar 遮挡 -->
       <view style="height: 200rpx;"></view>
     </scroll-view>
@@ -40,7 +55,14 @@
     <view class="bottom-bar">
       <button class="btn-offline" bindtap="onPayOffline" loading="{{submitting}}">线下支付</button>
       <button class="btn-online" bindtap="onPayOnline" loading="{{submitting}}">
-        ¥{{totalPrice}} 线上支付
+        <view wx:if="{{discountPrice > 0}}" class="price-display">
+          <text class="small-price">¥{{originalPrice}}</text>
+          <text class="main-price">¥{{totalPrice}}</text>
+        </view>
+        <view wx:else class="price-display">
+          <text class="main-price">¥{{totalPrice}}</text>
+        </view>
+        <text class="btn-text">线上支付</text>
       </button>
     </view>
   </block>
diff --git a/pages/apply/apply.wxss b/pages/apply/apply.wxss
index dcc962b..290ecf0 100644
--- a/pages/apply/apply.wxss
+++ b/pages/apply/apply.wxss
@@ -140,18 +140,64 @@
   font-size: 28rpx;
 }
 
-.coupon-icon {
+.coupon-btn {
   flex-shrink: 0;
-  width: 56rpx;
-  height: 56rpx;
-  display: flex;
-  align-items: center;
-  justify-content: center;
+  background: #1a56db;
+  color: #ffffff;
+  font-size: 26rpx;
+  padding: 0 32rpx;
+  height: 72rpx;
+  line-height: 72rpx;
+  border-radius: 36rpx;
+  margin-left: 24rpx;
 }
 
-.coupon-icon-text {
-  font-size: 44rpx;
-  color: #c0c4cc;
+.coupon-btn::after {
+  border: none;
+}
+
+/* ===== 金额显示区域 ===== */
+.price-section {
+  background: #ffffff;
+  border-radius: 24rpx;
+  padding: 32rpx;
+  margin-bottom: 24rpx;
+}
+
+.price-row {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  margin-bottom: 20rpx;
+}
+
+.price-row.total {
+  margin-bottom: 0;
+  padding-top: 20rpx;
+  border-top: 1rpx solid #f0f0f0;
+}
+
+.price-label {
+  font-size: 28rpx;
+  color: #666;
+}
+
+.original-price {
+  font-size: 28rpx;
+  color: #999;
+  text-decoration: line-through;
+}
+
+.discount-price {
+  font-size: 28rpx;
+  color: #e53935;
+  font-weight: 600;
+}
+
+.total-price {
+  font-size: 36rpx;
+  color: #1a56db;
+  font-weight: 700;
 }
 
 /* ===== 底部按钮栏 ===== */
@@ -177,6 +223,10 @@
   font-weight: 600;
   border: none;
   letter-spacing: 2rpx;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 16rpx;
 }
 
 .btn-offline {
@@ -197,19 +247,23 @@
   border: none;
 }
 
-
-.bottom-bar {
-  position: fixed;
-  left: 0;
-  right: 0;
-  bottom: 0;
-  padding: 18rpx 16rpx 24rpx;
-  background: rgba(255, 255, 255, 0.95);
-  border-top: 1rpx solid rgba(0, 0, 0, 0.06);
+.price-display {
+  display: flex;
+  align-items: baseline;
+  gap: 8rpx;
 }
 
-.submit-btn {
-  width: 100%;
-  height: 86rpx;
+.small-price {
+  font-size: 24rpx;
+  color: rgba(255, 255, 255, 0.7);
+  text-decoration: line-through;
 }
 
+.main-price {
+  font-size: 34rpx;
+  font-weight: 700;
+}
+
+.btn-text {
+  font-size: 28rpx;
+}
diff --git a/utils/constants.js b/utils/constants.js
index 4840a52..73c8aff 100644
--- a/utils/constants.js
+++ b/utils/constants.js
@@ -13,6 +13,7 @@ const API = {
   apply: '/api/eventclient/apply',
   calculateAmount: '/api/eventclient/calculate-amount',
   cancelRegistrationRefund: '/api/eventclient/cancel-registration-refund',
+  couponValidate: '/api/eventclient/coupon/validate',
 
   wechatLogin: '/api/oauth/login',
   loginByCode: '/api/oauth/login',