<el-table 
:header-cell-style="{textAlign: 'center'}" 
 :cell-style="{ textAlign: 'center' }"
 :data="tableData"
 stripe style="width: 100%">
<el-table-column prop="date" label="日期" width="144"></el-table-column>
</el-table>

表头水平居中
:header-cell-style="{textAlign: 'center'}" 
表格内容水平居中
 :cell-style="{ textAlign: 'center' }"