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