SOURCE

new Vue({
    el: '#app',
    data: {
        modelShow: true
    },
    methods: {
        showModel: function() {
            this.modelShow = true
        }
    }
})

<div id="app">
  <model v-model="modelShow">
      <div class="tt">弹窗内容</div>
  </model>

  <button v-on:click="showModel">显示弹窗</button>
</div>

@import url("//at.alicdn.com/t/font_1075539_mjkz0ben32.css");
.tt{
    width: 200px;
    height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
}
button{
    position: fixed;
    bottom: 10px;
    left: 45%;
}