1. function downFile(res, fileName) {
    2.   const blob = new Blob([res], {
    3.     type: `application/pdf;charset=UTF-8`
    4.   });
    6.   if (window.navigator.msSaveOrOpenBlob) {
    7.     // 兼容ie11
    8.     window.navigator.msSaveOrOpenBlob(blob, fileName);
    9.   } else {
    10.     const url = URL.createObjectURL(blob);
    11.     const downloadElement = document.createElement("a");
    12.     downloadElement.href = url;
    13.     downloadElement.download = fileName;
    14.     document.body.appendChild(downloadElement);
    15.     downloadElement.click();
    16.     downloadElement.remove();
    17.     URL.revokeObjectURL(url);
    18.   }
    19. }
    20. try {
    21.   this.$http.post("/api/company/bill/download", {
    22.     id,
    23.   }, {
    24.     responseType: 'blob'
    25.   }).then((res) => {
    26.     this.showLoading = false;
    27.     downFile(res, `123.pdf`)
    28.     return;
    29.   });
    30. } catch (error) {
    31.   console.error('error: ', error);
    32. }

    重点在于responseType: ‘blob’，指定已blob形式接收。
    接口返回的大致如下：
    image.png