el-select下拉弹窗样式修改首先在el-select上定义 popper-class="eloption" 和 :

首先在el-select上定义 popper-class="eloption" 和 :popper-append-to-body="true"

<el-select
  @change="handleSearch"
  v-model="params.evaluate"
  placeholder="请选择"
  popper-class="eloption"
  :popper-append-to-body="true"
>
  <el-option
    v-for="item in EvaluateStatusMap"
    :key="item.value"
    :label="item.label"
    :value="item.value">
  </el-option>
</el-select>

样式的话一定要注意不要加scoped

<style lang="scss">
.eloption{
  .el-select-dropdown__wrap{
    margin-bottom: 0 !important;
  }
}
</style>