diff --git a/frontend/src/pages/usr/UserDetail/constants.ts b/frontend/src/pages/usr/UserDetail/constants.ts
new file mode 100644
index 0000000..26fb820
--- /dev/null
+++ b/frontend/src/pages/usr/UserDetail/constants.ts
@@ -0,0 +1,155 @@
+// REQ-USR-001 / REQ-USR-002: 用户单据页合同级常量（枚举/默认/正则/错误码/文案 + 提交映射纯函数）
+import type {
+  UserCreateReq,
+  UserUpdateReq,
+  UserVO,
+  UserDetailMode,
+} from '../../../api/types';
+
+// === mode 常量（由路由 :id 判定） ===
+export const MODE_CREATE: UserDetailMode = 'create';
+export const MODE_EDIT: UserDetailMode = 'edit';
+
+// === 枚举（逐字一致，原样作为提交值，前端不映射，由后端裁决） ===
+/** 用户类型枚举，create 默认「普通用户」（BR6） */
+export const USER_TYPE_OPTIONS = ['普通用户', '超级管理员'] as const;
+/** 语言枚举（BR7，无默认强制选，create 必选） */
+export const LANGUAGE_OPTIONS = ['中文', '英文', '繁体'] as const;
+
+/**
+ * 受控表单值（spec § 6；`tCreateDate`/`sCreator` 只读展示态另存，不在提交值内）。
+ */
+export interface UserFormValues {
+  sUserName: string;
+  sUserNo: string;
+  iEmployeeId: number | null;
+  sUserType: string;
+  sLanguage: string | undefined;
+  iCanModifyBill: 0 | 1;
+  iIsVoid?: 0 | 1;
+}
+
+/** create 默认表单值（BR1/BR2/BR6/BR8；sLanguage 未选触发必填校验 BR7） */
+export const CREATE_DEFAULTS: UserFormValues = {
+  sUserName: '',
+  sUserNo: '',
+  iEmployeeId: null,
+  sUserType: '普通用户',
+  sLanguage: undefined,
+  iCanModifyBill: 0,
+  iIsVoid: 0,
+};
+
+/** 用户名前置校验正则（3-20 位字母数字下划线，BR3，对齐 docs/05 § REQ-USR-001） */
+export const USERNAME_PATTERN = /^[A-Za-z0-9_]{3,20}$/;
+
+// === 错误码常量（对齐 docs/05 § REQ-USR-001 / § REQ-USR-002 / spec § 4） ===
+/** 参数校验失败 */
+export const ERR_VALIDATION = 40001;
+/** 用户名已存在（仅 create） */
+export const ERR_USERNAME_EXISTS = 40901;
+/** 用户不存在（仅 edit） */
+export const ERR_USER_NOT_FOUND = 40401;
+/** 无权限 */
+export const ERR_NO_PERMISSION = 40301;
+
+// === 静态文案（逐字一致，复刻原型 / spec） ===
+export const TEXT_SAVE = '保存';
+export const TEXT_CANCEL = '取消';
+export const TEXT_NEW = '新增';
+export const TEXT_DELETE = '删除';
+export const TEXT_VOID = '作废';
+export const TEXT_RESET_PWD = '重置密码';
+export const TEXT_UNVOID = '取消作废';
+export const TEXT_FUNC = '功能';
+
+export const TEXT_CREATOR_PLACEHOLDER = '保存后自动生成';
+export const LABEL_CREATE_TIME = '创建时间';
+export const LABEL_CREATOR = '制单人';
+export const LABEL_EMPLOYEE = '员工名';
+export const LABEL_USERNAME = '用户名';
+export const LABEL_USER_TYPE = '类型';
+export const LABEL_LANGUAGE = '语言';
+export const LABEL_USER_NO = '用户号';
+export const LABEL_CAN_MODIFY_BILL = '单据修改权限';
+
+export const TAB_PERM_GROUP = '权限组';
+/** 5 个占位查看权限页签（D9） */
+export const PLACEHOLDER_TABS = [
+  '客户查看权限',
+  '供应商查看权限',
+  '人员查看权限',
+  '工序查看权限',
+  '司机查看权限',
+] as const;
+export const PERM_LIST_HEADER = '权限分类';
+
+// 校验提示
+export const MSG_USERNAME_FORMAT = '用户名须为 3-20 位字母数字下划线';
+export const MSG_USERNAME_REQUIRED = '请输入用户名';
+export const MSG_USERNO_REQUIRED = '请输入用户号';
+export const MSG_USERTYPE_REQUIRED = '请选择类型';
+export const MSG_LANGUAGE_REQUIRED = '请选择语言';
+
+// 成功 / 错误反馈
+export const MSG_CREATE_SUCCESS = '用户创建成功';
+export const MSG_EDIT_SUCCESS = '保存成功';
+export const MSG_ERR_VALIDATION = '提交信息有误，请检查后重试';
+export const MSG_ERR_USERNAME_EXISTS = '用户名已存在，请更换';
+export const MSG_ERR_USER_NOT_FOUND = '该用户不存在或已被删除';
+export const MSG_ERR_NO_PERMISSION = '无权限执行此操作';
+export const MSG_ERR_NETWORK = '保存失败，请稍后重试';
+export const MSG_ERR_LOAD_EMPLOYEES = '员工列表加载失败';
+export const MSG_ERR_LOAD_PERMISSIONS = '权限列表加载失败';
+export const MSG_LOAD_DETAIL_FAIL = '加载失败，点击重试';
+export const MSG_CANCEL_CONFIRM = '放弃未保存的修改？';
+export const MSG_FUNC_PLACEHOLDER = '功能开发中';
+export const TEXT_BACK_TO_LIST = '返回列表';
+
+// 路由 path（FE-02 已注册占位）
+export const PATH_USER_LIST = '/usr/users';
+export const PATH_USER_NEW = '/usr/users/new';
+
+// === 提交映射纯函数（跨 task 一致，便于单测） ===
+
+/** 表单值 + 勾选权限 → UserCreateReq（无密码，BR9） */
+export function toCreateReq(values: UserFormValues, permissionIds: number[]): UserCreateReq {
+  return {
+    sUserName: values.sUserName,
+    sUserNo: values.sUserNo,
+    iEmployeeId: values.iEmployeeId,
+    sUserType: values.sUserType,
+    sLanguage: values.sLanguage ?? '',
+    iCanModifyBill: values.iCanModifyBill,
+    permissionIds,
+  };
+}
+
+/** 表单值 + 勾选权限 → UserUpdateReq（不含 sUserName，BR3；permissionIds 全量覆盖，BR11） */
+export function toUpdateReq(values: UserFormValues, permissionIds: number[]): UserUpdateReq {
+  return {
+    sUserNo: values.sUserNo,
+    iEmployeeId: values.iEmployeeId,
+    sUserType: values.sUserType,
+    sLanguage: values.sLanguage ?? '',
+    iCanModifyBill: values.iCanModifyBill,
+    iIsVoid: values.iIsVoid ?? 0,
+    permissionIds,
+  };
+}
+
+/**
+ * edit 回填（BR17）。`UserVO`（FE-03 列表 VO）不暴露 `iCanModifyBill`，
+ * 故该字段默认 0；其余基本字段按原值回填。
+ */
+export function userVoToFormValues(vo: UserVO): UserFormValues {
+  return {
+    sUserName: vo.sUserName,
+    sUserNo: vo.sUserNo ?? '',
+    iEmployeeId: null,
+    sUserType: vo.sUserType,
+    sLanguage: vo.sLanguage,
+    iCanModifyBill: 0,
+    iIsVoid: (vo.iIsVoid === 1 ? 1 : 0) as 0 | 1,
+  };
+}
diff --git a/frontend/tests/unit/userDetailMappers.test.ts b/frontend/tests/unit/userDetailMappers.test.ts
new file mode 100644
index 0000000..285f432
--- /dev/null
+++ b/frontend/tests/unit/userDetailMappers.test.ts
@@ -0,0 +1,97 @@
+// REQ-USR-001 / REQ-USR-002: 用户单据常量与提交映射纯函数单测（枚举/默认/正则/错误码 + toCreateReq/toUpdateReq/userVoToFormValues）
+import { describe, it, expect } from 'vitest';
+import {
+  USER_TYPE_OPTIONS,
+  LANGUAGE_OPTIONS,
+  CREATE_DEFAULTS,
+  USERNAME_PATTERN,
+  ERR_VALIDATION,
+  ERR_USERNAME_EXISTS,
+  ERR_USER_NOT_FOUND,
+  ERR_NO_PERMISSION,
+  MODE_CREATE,
+  MODE_EDIT,
+  toCreateReq,
+  toUpdateReq,
+  userVoToFormValues,
+  type UserFormValues,
+} from '../../src/pages/usr/UserDetail/constants';
+import type { UserVO } from '../../src/api/types';
+
+function makeFormValues(over: Partial<UserFormValues> = {}): UserFormValues {
+  return {
+    sUserName: 'zhangsan',
+    sUserNo: 'zs',
+    iEmployeeId: 3,
+    sUserType: '普通用户',
+    sLanguage: '中文',
+    iCanModifyBill: 0,
+    iIsVoid: 0,
+    ...over,
+  };
+}
+
+describe('用户单据常量与映射', () => {
+  it('constants enums and defaults', () => {
+    expect(USER_TYPE_OPTIONS).toEqual(['普通用户', '超级管理员']);
+    expect(LANGUAGE_OPTIONS).toEqual(['中文', '英文', '繁体']);
+    expect(CREATE_DEFAULTS.sUserType).toBe('普通用户');
+    expect(CREATE_DEFAULTS.iCanModifyBill).toBe(0);
+    expect(CREATE_DEFAULTS.sLanguage).toBeUndefined();
+    expect(USERNAME_PATTERN.test('ab_12')).toBe(true);
+    expect(USERNAME_PATTERN.test('ab')).toBe(false);
+    expect(USERNAME_PATTERN.test('有中文')).toBe(false);
+    expect(ERR_VALIDATION).toBe(40001);
+    expect(ERR_USERNAME_EXISTS).toBe(40901);
+    expect(ERR_USER_NOT_FOUND).toBe(40401);
+    expect(ERR_NO_PERMISSION).toBe(40301);
+    expect(MODE_CREATE).toBe('create');
+    expect(MODE_EDIT).toBe('edit');
+  });
+
+  it('toCreateReq maps form values + permissionIds (no password)', () => {
+    const req = toCreateReq(makeFormValues({ iCanModifyBill: 1 }), [1, 2]);
+    expect(req.sUserName).toBe('zhangsan');
+    expect(req.sUserNo).toBe('zs');
+    expect(req.iEmployeeId).toBe(3);
+    expect(req.sUserType).toBe('普通用户');
+    expect(req.sLanguage).toBe('中文');
+    expect(req.iCanModifyBill).toBe(1);
+    expect(req.permissionIds).toEqual([1, 2]);
+    expect(req).not.toHaveProperty('initialPassword');
+    expect(req).not.toHaveProperty('iIsVoid');
+  });
+
+  it('toUpdateReq maps without sUserName + includes iIsVoid + full permissionIds', () => {
+    const req = toUpdateReq(makeFormValues({ iIsVoid: 1 }), [2, 3]);
+    expect(req).not.toHaveProperty('sUserName');
+    expect(req.iIsVoid).toBe(1);
+    expect(req.permissionIds).toEqual([2, 3]);
+    expect(req.sUserType).toBe('普通用户');
+    expect(req.sLanguage).toBe('中文');
+    expect(req.iCanModifyBill).toBe(0);
+  });
+
+  it('userVoToFormValues fills from UserVO', () => {
+    const vo: UserVO = {
+      id: 7,
+      sUserName: 'zhangsan',
+      employeeName: '张三',
+      sUserNo: 'zs',
+      departmentName: null,
+      sUserType: '超级管理员',
+      sLanguage: '英文',
+      iIsVoid: 1,
+      tLastLoginDate: null,
+      sCreator: 'admin',
+      tCreateDate: '2026-01-01T00:00:00',
+    };
+    const fv = userVoToFormValues(vo);
+    expect(fv.sUserName).toBe('zhangsan');
+    expect(fv.sUserNo).toBe('zs');
+    expect(fv.sUserType).toBe('超级管理员');
+    expect(fv.sLanguage).toBe('英文');
+    expect(fv.iCanModifyBill).toBe(0);
+    expect(fv.iIsVoid).toBe(1);
+  });
+});