<!-- 父组件A wxml -->
<view>
 <componentB paramAtoB='{{paramAtoB}}'></componentB>
</view>

{
 "navigationBarTitleText": "父子传值",
 "usingComponents": {
  "componentB": "../../components/son/son"
 }
}

//父组件A js
// view/father/father.js
Page({
 /**
  * 页面的初始数据
  */
 data: {
  paramAtoB: "我是A向B传值"
 }
})

<!-- 子组件B wxml -->
<view class="inner">
 {{paramAtoB}}
</view>

//子组件B js
Component({
 //B在这里接收与data类似可以直接在wxml上用
 properties: {
  paramAtoB: {
   type: String,//类型
   value: 'default value'//默认值
  }
 },
 data: {  
 }
})

{
 "component": true,
 "usingComponents": {}
}

<!-- 父组件A wxml -->
<view>
 <componentB paramAtoB='{{paramAtoB}}' bind:myevent="onMyEvent"></componentB>
 {{ paramBtoA }}
</view>

// view/father/father.js
Page({

 /**
  * 页面的初始数据
  */
 data: {
  paramAtoB: "我是A向B传值",
  paramBtoA: 1122
 },
 onMyEvent: function (e) {
  //通过事件接收
  this.setData({
   paramBtoA: e.detail.paramBtoA
  })
 }
})

{
 "navigationBarTitleText": "父子传值",
 "usingComponents": {
  "componentB": "../../components/son/son"
 }
}

<!-- 子组件B wxml -->
<view class="inner">
 {{paramAtoB}}
 <button bindtap='change'>向A中传入参数</button>
</view>

//子组件B js
Component({
 //B在这里接收与data类似可以直接在wxml上用
 properties: {
  paramAtoB: {
   type: String,//类型
   value: 'default value'//默认值
  }
 },
 data: {
  
 },
 methods: {
  //触发change事件向A传值
  change: function () {
   this.triggerEvent('myevent', { paramBtoA: "666传值成功" });
  }
 }
})

{
 "component": true,
 "usingComponents": {}
}