diff --git a/doc/api.md b/doc/api.md
index d75a3d1..2c220b2 100644
--- a/doc/api.md
+++ b/doc/api.md
@@ -814,5 +814,29 @@
 "sendTime": 1623316467010,									// 公告发送时间
 "title": "111",															// 公告标题
 "type": 2																		// 公告类型 0: 普通 1: 店铺群发 2: 全体
+}
+```
+
+### 23. 开始分享优惠券
+
+1. Method: POST
+2. <span id="222">URI: /api/:accountId/coupon/begin_share</span>
+
+| 字段     | 说明                                   |
+| -------- | -------------------------------------- |
+| accountid | 帐号id                             |
+
+> POST参数
+
+
+| 字段     | 说明                                   |
+| -------- | -------------------------------------- |
+| id | 优惠券的短id  		|
+
+3. Response: JSON
+
+```js
+{
+
 }
 ```
\ No newline at end of file
diff --git a/src/api/controllers/coupon.controller.ts b/src/api/controllers/coupon.controller.ts
new file mode 100644
index 0000000..9ad6473
--- /dev/null
+++ b/src/api/controllers/coupon.controller.ts
@@ -0,0 +1,48 @@
+import { role, router } from 'decorators/router'
+import { UserCoupon } from 'models/user/UserCoupon'
+import BaseController from '../../common/base.controller'
+import { ZError } from '../../common/ZError'
+
+class CouponController extends BaseController {
+  /**
+   * 获取优惠券信息
+   */
+  @role('anon')
+  @router('get /pub/coupon/:shop/:id')
+  async info(req: any) {
+    return {}
+  }
+  /**
+   * 核销
+   */
+  @role('anon')
+  @router('post /pub/coupon/:shop/:id')
+  async use(req: any) {
+    return {}
+  }
+  /**
+   * 开始分享, 将当前优惠券改为正在分享状态
+   */
+  @role('anon')
+  @router('post /api/:accountId/coupon/begin_share')
+  async beginShare(req: any) {
+    let { accountId, id } = req.params
+    if (!id) {
+      throw new ZError(10, '缺少必要参数: id')
+    }
+    const result = await UserCoupon.updateOne({ sid: id, status: { $in: [0, 2] }, accountId }, { status: 2 })
+    if (result.nModified !== 1) {
+      throw new ZError(11, 'no matched records')
+    }
+    return result
+  }
+
+  /**
+   * 接受分享出去的优惠券
+   */
+  @role('anon')
+  @router('post /api/:accountId/coupon/receive_coupon')
+  async receive(req: any) {
+    return {}
+  }
+}
diff --git a/src/models/user/UserCoupon.ts b/src/models/user/UserCoupon.ts
index f6254da..dcf52a5 100644
--- a/src/models/user/UserCoupon.ts
+++ b/src/models/user/UserCoupon.ts
@@ -12,6 +12,7 @@ const nanoid = customAlphabet('2345678abcdefghjkmnpqrstwxy', 10)
 
 @dbconn()
 @index({ accountId: 1, shop: 1 }, { unique: false })
+@index({ sid: 1, shop: 1 }, { unique: true })
 @index({ accountId: 1, shop: 1, item: 1 }, { unique: false })
 @modelOptions({ schemaOptions: { collection: 'user_coupons', timestamps: true } })
 @pre<UserCouponClass>('save', async function () {
@@ -19,34 +20,49 @@ const nanoid = customAlphabet('2345678abcdefghjkmnpqrstwxy', 10)
     let sid = ''
     while (!sid) {
       sid = nanoid()
-      const records = await UserCoupon.find({ sid }, { _id: 1 }).limit(1)
+      const records = await UserCoupon.find({ sid, shop: this.shop }, { _id: 1 }).limit(1)
       records.length > 0 && (sid = '')
     }
     this.sid = sid
   }
 })
 class UserCouponClass extends BaseModule {
+  /**
+   * 当前拥有者的帐号id
+   */
   @prop()
   public accountId: string
-
+  /**
+   * 所属店铺id
+   */
   @prop()
   public shop: string
-
+  /**
+   * 真实的优惠券id
+   */
   @prop()
   public item: string
-
+  /**
+   * 短id, 用于生成二维码, 店铺唯一
+   */
   @prop()
   public sid: string
 
   @prop({ default: 0 })
   public count: number
-
+  /**
+   * 来源
+   */
   @prop()
   public source: string
-
+  /**
+   * 活动or挑战id
+   */
   @prop()
   public activityId: string
-
+  /**
+   * UserReward的记录id
+   */
   @prop()
   public rewardId: string
 
@@ -54,6 +70,8 @@ class UserCouponClass extends BaseModule {
    * 状态
    * 0: 未使用
    * 1: 已使用
+   * 2: 赠送中
+   * 3: 已赠送
    * 9: 已过期
    * @type {number}
    */
diff --git a/src/models/user/UserReward.ts b/src/models/user/UserReward.ts
index 4175dd1..bb5ea19 100644
--- a/src/models/user/UserReward.ts
+++ b/src/models/user/UserReward.ts
@@ -134,7 +134,14 @@ class UserRewardClass extends BaseModule {
       rewardType,
     }
   }
-
+  /**
+   * 添加一条奖励获取记录
+   * @param history 挑战记录
+   * @param accountId 帐号信息
+   * @param rewardId  奖励id
+   * @param coupon    优惠券id
+   * @param count     数量
+   */
   public static async addOneRecord(
     history: PuzzleSessionClass,
     accountId: string,
@@ -165,7 +172,10 @@ class UserRewardClass extends BaseModule {
     let source = history.type === 1 ? 'activity' : 'exam'
     return UserReward.rewardGot({ accountId, shop: history.shop, rewardId, activityId: history.activityId, source })
   }
-
+  /**
+   * 判断特定条件下一个奖励是否已经获取
+   * @returns {Boolean}
+   */
   public static async rewardGot({
     accountId,
     shop,
@@ -185,7 +195,13 @@ class UserRewardClass extends BaseModule {
     ).limit(1)
     return records.length > 0
   }
-
+  /**
+   * 获取已经获得的奖励奖励信息, 用于判断指定的reward是否已经获得过了
+   * @param accountId 帐号id
+   * @param shop      所属店铺
+   * @param activityId  活动id
+   * @returns {Set<String>} 由reward id组成的Set
+   */
   public static async userGotSet(accountId: string, shop: string, activityId: string) {
     let records = await UserReward.find({ accountId, shop, activityId })
     let result: Set<string> = new Set()