例：效果

    <el-form-item label="新密码" prop="newPassword">
      <el-input v-model="user.newPassword" placeholder="请输入新密码" type="password" />
    </el-form-item>
    <el-form-item label="确认密码" prop="confirmPassword">
      <el-input v-model="user.confirmPassword"  placeholder="请确认密码" type="password" />
    </el-form-item>
    <el-form-item>
      <el-button type="primary" size="mini" @click="modifyPwd">保存</el-button>
    </el-form-item>
  </el-form>
   </el-dialog>

data() {
      const equalToPassword = (rule, value, callback) => {
      if (this.user.newPassword !== value) {
        callback(new Error("两次输入的密码不一致"));
      } else {
        callback();
      }
    };
    return {
      // 版本号
      version: "3.2.1",
      dialogTableVisible: false,
      currentUser:{},
      currentUserId:undefined,
      user: {
        newPassword: undefined,
        confirmPassword: undefined
      },
 
  // 表单校验
      rules: {
        newPassword: [
          { required: true, message: "新密码不能为空", trigger: "blur" },
          { min: 8, max: 12, message: "长度在 8 到 12个字符", trigger: "blur" }
        ],
        confirmPassword: [
          { required: true, message: "确认密码不能为空", trigger: "blur" },
          { required: true, validator: equalToPassword, trigger: "blur" }
        ]
      }

如果需要隐藏展示密码只需要一个属性，这个是element-ui自带的属性 ：show-password

<el-input v-model="ruleForm.password" show-password maxlength="50" type="text" size="small" placeholder="请输入密码" />