// flex 布局。。。
<radio-group class="radio-list" bindchange="radioChange">
  <label wx:for="{{items}}" wx:key="{{item.value}}">
    <radio value="{{item.value}}" checked="true" />{{item.name}}
  </label>
</radio-group>

.radio-list {
  width: 100%;
  display: flex;
  flex-direction: column;
}

data: {
  items: [
    {value: 'USA', name: '美国'},
    {value: 'CHN', name: '中国', checked: 'true'},
    {value: 'BRA', name: '巴西'},
    {value: 'JPN', name: '日本'},
    {value: 'ENG', name: '英国'},
    {value: 'FRA', name: '法国'},
  ]
}