原生的show-overflow-tooltip=“true” 不能满足条件，使用插槽自定义编辑；

旧code

<el-table-column prop="reason" label="原因" align="center" :show-overflow-tooltip="true" />
<el-table-column prop="params" label="参数" align="center" :show-overflow-tooltip="true" />

新code

<el-table-column prop="reason" label="原因" align="center">
  <template slot-scope="scope">
    <el-tooltip class="item" effect="dark" placement="top-start">
      <div slot="content">{{ scope.row.reason }}</div>
      <div style="max-width: 200px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;">
        {{ scope.row.reason }}
      </div>
    </el-tooltip>
  </template>
</el-table-column>
<el-table-column prop="params" label="参数" align="center">
  <template slot-scope="scope">
    <el-tooltip class="item" effect="dark" placement="top-start">
      <div slot="content">{{ scope.row.params }}</div>
      <div style="max-width: 200px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;">
        {{ scope.row.params }}
      </div>
    </el-tooltip>
  </template>
</el-table-column>

新css样式

.el-tooltip__popper {
  max-width: 500px !important; /* 你想要的宽度 */
}

效果