diff --git a/frontend/src/pages/roster/modals.tsx b/frontend/src/pages/roster/modals.tsx
index 6d63023..6bf9523 100644
--- a/frontend/src/pages/roster/modals.tsx
+++ b/frontend/src/pages/roster/modals.tsx
@@ -110,9 +110,22 @@ export function DeptChangeModal({ employee, onClose, onSubmit, loading, error }:
   }
   buildDeptOptions(departments, null, 0)
 
-  // 选中新部门后，过滤该部门下的职务（如果职务有 departmentId 关联）
+  // 选中新部门后，过滤该部门下的职务：
+  // 1. 通用职务（departmentId 为空）所有部门可用
+  // 2. 该部门专属职务
+  // 3. 父部门专属职务（子部门继承父部门职务，如铁矿继承项目运营中心的工人/施工员等）
+  const getDeptAncestorIds = (deptId: string): string[] => {
+    const ids: string[] = []
+    let cur: any = departments.find((d: any) => d.id === deptId)
+    while (cur) {
+      ids.push(cur.id)
+      cur = cur.parentId ? departments.find((d: any) => d.id === cur.parentId) : null
+    }
+    return ids
+  }
+  const ancestorIds = form.departmentId ? getDeptAncestorIds(form.departmentId) : []
   const filteredPositions = form.departmentId
-    ? positions.filter((p: any) => !p.departmentId || p.departmentId === form.departmentId)
+    ? positions.filter((p: any) => !p.departmentId || ancestorIds.includes(p.departmentId))
     : positions
 
   const selectedDept = departments.find((d: any) => d.id === form.departmentId)