<div ref="myContainer" id="fatherWidh">
            <el-table
              id="factTable">
...
</el-table>
</div>

import html2canvas from "html2canvas";
import jsPDF from "jspdf";

handleExport(id) {
      this.generatePDF(this.$refs.myContainer, "排班统计表");
    },
    generatePDF(el, name) {
      let parent = el.offsetParent;
      let grandParent = parent.offsetParent;
      let left = grandParent.offsetLeft + parent.offsetLeft + el.offsetLeft;
      let top = grandParent.offsetTop + parent.offsetTop + el.offsetTop;
      let tableWidth = document.querySelector(
        "#factTable .el-table__body-wrapper"
      );
      // factTable 是我在 el-table 上指定的 id
      // .el-table__body-wrapper 是组件自动生成的带滚动条的 div 上的 class (需要在浏览器的开发者工具中查找)
      // 重要：设置表格父节点的宽度，最后再把宽度恢复成100%
      document.getElementById(
        "fatherWidh"
      ).style.width = `${tableWidth.scrollWidth}px`;

      console.log("-----", tableWidth.scrollWidth);

      html2canvas(el, {
        // x: left,
        // y: top,
        ///  here！！！！！！！ ///
        width: tableWidth.scrollWidth + 60, // 为了使横向滚动条的内容全部展示，这里必须指定！！
        // 注意id需在html代码中指定。
        // eg:html某div中指定了‘id="myDiv"’，此处写为‘getElementById("myDiv")’，则pdf以myDiv的宽度为准
      }).then((canvas) => {
        let contentWidth = canvas.width;
        let contentHeight = canvas.height;
        //一页pdf显示html页面生成的canvas高度;
        // eslint-disable-next-line no-extra-parens
        let pageHeight = (contentWidth / 592.28) * 841.89;
        //未生成pdf的html页面高度
        let leftHeight = contentHeight;
        //页面偏移
        let position = 0;
        //a4纸的尺寸[595.28,841.89]，html页面生成的canvas在pdf中图片的宽高
        let imgWidth = 595.28;
        // eslint-disable-next-line no-extra-parens
        let imgHeight = (592.28 / contentWidth) * contentHeight;
        let pageData = canvas.toDataURL("image/jpeg", 1.0);
        let pdf = new jsPDF("", "pt", "a4");
        //有两个高度需要区分，一个是html页面的实际高度，和生成pdf的页面高度(841.89)
        //当内容未超过pdf一页显示的范围，无需分页
        if (leftHeight < pageHeight) {
          pdf.addImage(pageData, "JPEG", 5, 30, imgWidth, imgHeight);
        } else {
          while (leftHeight > 0) {
            //arg3-->距离左边距;arg4-->距离上边距;arg5-->宽度;arg6-->高度
            pdf.addImage(pageData, "JPEG", 5, position, imgWidth, imgHeight);
            leftHeight -= pageHeight;
            position -= 841.89;
            //避免添加空白页
            if (leftHeight > 0) {
              //添加新页
              pdf.addPage();
            }
          }
        }
        pdf.save(`${name}.pdf`);
        document.getElementById("fatherWidh").style.width = `${100}%`;
      });
    },

参考：https://blog.csdn.net/Bule_daze/article/details/111244892?spm=1001.2101.3001.6650.1&utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7Edefault-1-111244892-blog-125203111.pc_relevant_multi_platform_whitelistv2&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7Edefault-1-111244892-blog-125203111.pc_relevant_multi_platform_whitelistv2&utm_relevant_index=1