diff --git a/API.md b/API.md
index 7fb807c..ac470bd 100644
--- a/API.md
+++ b/API.md
@@ -500,6 +500,7 @@ Base 前缀 `/api/v1/admin`。
 | 方法 | 路径 | 说明 |
 |---|---|---|
 | `GET` | `/api/v1/platform/employees` | 列全平台未软删员工;包含停用、锁定及无平台角色用户 |
+| `POST` | `/api/v1/platform/employees` | 创建平台员工账号(返回 201);不自动加入任何 workspace |
 | `GET` | `/api/v1/platform/workspaces` | 列 workspace(`active`/`archived`);已软删的过滤掉 |
 | `POST` | `/api/v1/platform/workspaces` | 创建 workspace(返回 201);创建者自动成为 admin 成员 |
 | `GET` | `/api/v1/platform/workspaces/{workspace_id}` | 单个 workspace(含已 disabled 的,用于恢复) |
@@ -596,7 +597,8 @@ Base 前缀 `/api/v1/admin`。
 | `role_code` | string | 是 | `admin` \| `developer` | **不可填 `system_admin`**(那是用户级身份,不是 workspace 角色) |
 
 - 服务端默认 `member_status='active'`。
-- 用户不存在 → 404;用户已是该 workspace 成员 → 409。
+- 用户不存在或已软删除 → 404;用户状态不是 `active` → 409;用户已是该 workspace 成员 → 409。
+- 新员工必须先通过 `POST /api/v1/platform/employees` 或现有 workspace 员工创建接口建立用户账号。
 
 ### 7.6 `PATCH /api/v1/platform/workspaces/{workspace_id}/members/{user_id}`
 
@@ -647,6 +649,26 @@ Base 前缀 `/api/v1/admin`。
   }
   ```
 
+### 7.9 `POST /api/v1/platform/employees`
+
+只创建平台员工账号,不创建任何 `workspace_members` 记录。调用者必须是系统管理员;已认证但不是系统管理员时返回 `403`。
+
+- **请求体字段**:
+
+| 字段 | 类型 | 必填 | 限制 | 说明 |
+|---|---|---|---|---|
+| `username` | string | 是 | 2~64 字符 | 全平台唯一登录名 |
+| `display_name` | string | 是 | 1~100 字符 | 显示名称 |
+| `email` | string | 否 | ≤255 字符 | 邮箱,全平台唯一 |
+| `password` | string | 是 | 8~72 字符 | 登录密码 |
+
+- 新用户状态固定为 `active`,且不分配平台角色。
+- 密码使用 bcrypt 哈希保存;响应不包含 `password` 或 `password_hash`。
+- 用户名或邮箱重复 → 409。
+- 创建成功后,可调用 `POST /api/v1/platform/workspaces/{workspace_id}/members` 将用户加入指定 workspace。
+
+- **响应 201**:字段与 §7.8 的员工元素一致,其中 `role_code`、`role_name` 均为 `null`,`meta` 为空对象。
+
 ---
 
 ## 八、Jupyter 路由
diff --git a/backend/src/backend/platform.py b/backend/src/backend/platform.py
index a4937f7..85a9fb8 100644
--- a/backend/src/backend/platform.py
+++ b/backend/src/backend/platform.py
@@ -28,6 +28,7 @@ Workspace membership CRUD::
 Platform employee roster::
 
     GET    /employees                          — list all non-deleted users
+    POST   /employees                          — create a user without workspace membership
 
 Invariants
 ----------
@@ -50,10 +51,11 @@ from typing import Any, Literal
 
 from fastapi import APIRouter, Depends, HTTPException, Request, status
 from pydantic import BaseModel, ConfigDict, Field
-from sqlalchemy import func, select, update
+from sqlalchemy import func, or_, select, update
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from backend.dependencies import current_user, database_session
+from common.auth.passwords import hash_password
 from common.db.models import Roles, Users, WorkspaceMembers, Workspaces
 from common.ids import new_ulid
 
@@ -111,6 +113,15 @@ class MemberUpdate(BaseModel):
     member_status: Literal["active", "disabled", "locked"] | None = None
 
 
+class PlatformEmployeeCreate(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    username: str = Field(min_length=2, max_length=64)
+    display_name: str = Field(min_length=1, max_length=100)
+    email: str | None = Field(default=None, max_length=255)
+    password: str = Field(min_length=8, max_length=72)
+
+
 # ---------------------------------------------------------------------------
 # System-admin context dependency
 # ---------------------------------------------------------------------------
@@ -302,6 +313,39 @@ async def list_platform_employees(
     )
 
 
+@router.post("/employees", status_code=status.HTTP_201_CREATED)
+async def create_platform_employee(
+    payload: PlatformEmployeeCreate,
+    context: SystemAdminContext = Depends(system_admin_context),
+    session: AsyncSession = Depends(database_session),
+) -> dict[str, Any]:
+    """Create a platform user without assigning workspace membership."""
+    username = payload.username.strip()
+    display_name = payload.display_name.strip()
+    duplicate_conditions = [Users.username == username]
+    if payload.email:
+        duplicate_conditions.append(Users.email == payload.email.strip())
+    duplicate = await session.scalar(
+        select(Users.user_id).where(or_(*duplicate_conditions))
+    )
+    if duplicate is not None:
+        raise HTTPException(status.HTTP_409_CONFLICT, "用户名或邮箱已存在")
+
+    user = Users(
+        user_id=new_ulid(),
+        username=username,
+        display_name=display_name,
+        email=payload.email.strip() if payload.email else None,
+        password_hash=hash_password(payload.password),
+        status="active",
+        platform_role_id=None,
+    )
+    session.add(user)
+    await session.flush()
+    await session.refresh(user)
+    return _envelope(context.request_id, platform_employee_payload(user, None))
+
+
 # ---------------------------------------------------------------------------
 # Workspace CRUD
 # ---------------------------------------------------------------------------
@@ -502,8 +546,13 @@ async def add_member(
     """Add a user to a workspace. The new row starts with member_status='active'."""
     await _load_workspace(session, workspace_id)
     user = await session.get(Users, payload.user_id)
-    if user is None:
+    if user is None or user.is_deleted != 0:
         raise HTTPException(status.HTTP_404_NOT_FOUND, "用户不存在")
+    if user.status != "active":
+        raise HTTPException(
+            status.HTTP_409_CONFLICT,
+            f"用户状态为 {user.status},无法加入 workspace",
+        )
     role = await _load_role_by_code(session, payload.role_code)
     duplicate = await session.scalar(
         select(WorkspaceMembers.user_id).where(