方法一：给组件加id / class，在style一面直接修改，注意style不要加scoped,vue可以有多个style
结构：

<template>
  <Modal v-model="params.modal1" :title="tit" :mask-closable="false" id="noAssessmentDate">
    <Row>
      <Col span="24">
      <span>选择日期:</span>
      <DatePicker type="date" placeholder="开始日期" :options="options" v-model="startTime" style="width: 200px"></DatePicker>
      <span>至</span>
      <DatePicker type="date" placeholder="结束日期" :options="options" v-model="endTime" style="width: 200px"></DatePicker>
      <Button type="success" style="margin-left:20px" @click="add">添加</Button>
      </Col>
    </Row>
    <div style="padding:20px 0">
      <Tag v-for="(item,index) in list" :closable='item.closeable' :key="index" v-if="item.time" @on-close="handleClose(index)">{{item.time}}</Tag>
    </div>
    <div slot="footer">
    </div>
  </Modal>
</template>

样式：

<style>
#noAssessmentDate .ivu-modal {
  width: 686px !important;
}
#noAssessmentDate .ivu-tag {
  width: 105px;//修改tag的宽度
}
#noAssessmentDate .ivu-icon-ios-close-empty:before {
  color: red; //红x
}
</style>

方法二：
利用深度/deep/深度修改组建的样式，可以直接写在到scoped作用域的style里面。（推荐）
结构：

<Table :columns='tableColums' :data='tableData' stripe id="tab_keyTag" ref="table" @on-selection-change='selectionChange'></Table>

<style scoped>
#tab_keyTag /deep/ .ivu-table .ivu-table-header .ivu-checkbox {
  display: none;
  cursor: none;
}
#tab_keyTag /deep/ .ivu-table .ivu-table-header label:after {
  content: "选择";
}
#tab_keyTag /deep/ .ivu-table .ivu-table-header .ivu-checkbox-wrapper {
  cursor: default;
  pointer-events: none;
}
</style>