el-table中添加:row-key=“getRowKeys”
设置true【 :reserve-selection=“true”】

javascript">:row-key="getRowKeys" <el-table-column type="selection" :reserve-selection="true" width="55" align="center" fixed="left" />

<el-table ref="multipleTable" :row-key="getRowKeys" :data="tableData" role="table"height="100%" @selection-change="handleSelectionChange":header-cell-style="{ background: '#1890ff', color: '#fff', fontSize: '14px', fontFamily: 'SourceHanSansSC-Medium', fontWeight: '500' }"size="small"><el-table-column type="selection" :reserve-selection="true" width="55" align="center" fixed="left" /><el-table-column type="expand" width="55" fixed="left"> <template slot-scope="props"><el-form style="padding: 0 20px;" label-position="left" inline class="demo-table-expand"><el-form-item :style="'width:380px'" v-for="(i, j) in columns" :label="i.label + '：'" :key="j"><span>{{ props.row[i.prop] }}</span></el-form-item></el-form></template></el-table-column><el-table-column type="index" :index="indexMethod" width="55" align="center" label="序号" /><template v-for="(item, index) in columns"><el-table-column v-if="queryParams.layout && item.abstract" :key="index" show-overflow-tooltip:label="item.label" align="center" :width="item.width"><template slot-scope="scope"><span>{{ scope.row[item.prop] }}</span></template></el-table-column><el-table-column v-if="!queryParams.layout" :key="index" show-overflow-tooltip :label="item.label"align="center" :width="item.width"><template slot-scope="scope"><span>{{ scope.row[item.prop] }}</span></template></el-table-column></template></el-table>

javascript"> getRowKeys(row) {return row.id},

清空多选

javascript"> this.$refs.multipleTable.clearSelection()