1.给select设置一个key,options数据更新后刷新key——解决无法更新显示label问题
2.设置remote、filterable为true,动态更新options下拉列表。此时不要更新key(避免下拉框自动收起),在visible-change事件里面监听visible=false时再更更新key
<el-select v-model="value" placeholder="请选择" :key="selectKey"  :remote="true" filterable @visible-change="visibleChange">
    <el-option v-for="item in options" :key="item.value" :label="item.label" :value="item.value"></el-option>
</el-select>
data() {
    return {
      options: [],
      value: '',
      selectKey: 1
    };
  },
  mounted() {
    setTimeout(() => {
      this.value = '选项1';
      this.options = [
        {value: '选项1', label: '黄金糕'},
        {value: '选项2', label: '双皮奶'}
      ];
      this.selectKey++;
    }, 5000);
  },
  methods: {
    visibleChange(visible) {
      if (!visible) {
        this.selectKey++;
      } else {
        setTimeout(() => {
          // 更新下拉框
          this.options = [
            {value: '选项1', label: '黄金糕'},
            {value: '选项2', label: '双皮奶'},
            {value: '选项3', label: '莲子粥'},
            {value: '选项4', label: '豆沙包'},
          ];
        }, 2000);
      }
    }
  }
};