diff --git a/apps/user/cms_relation.py b/apps/user/cms_relation.py
index e116f73..f5605f7 100644
--- a/apps/user/cms_relation.py
+++ b/apps/user/cms_relation.py
@@ -34,26 +34,43 @@ class CmsRelationSerializer(serializers.ModelSerializer):
 
 
 class CmsRelationWriteSerializer(serializers.ModelSerializer):
-    """新增 / 编辑：teacher 必须是医生、student 必须是学生；医院管理员限本院。"""
-    teacher = serializers.PrimaryKeyRelatedField(queryset=User.objects.filter(role_type='doctor'))
-    student = serializers.PrimaryKeyRelatedField(queryset=User.objects.filter(role_type='student'))
+    """新增 / 编辑：入参用**带教老师手机号 / 学生手机号**；按手机号解析为用户
+    （带教老师须 doctor、学生须 student）；医院管理员限本院。"""
+    teacher_phone = serializers.CharField(write_only=True, required=False, help_text='带教老师手机号（新增必填）')
+    student_phone = serializers.CharField(write_only=True, required=False, help_text='学生手机号（新增必填）')
 
     class Meta:
         model = TeacherStudentRelation
-        fields = ['teacher', 'student', 'relation_type', 'status']
+        fields = ['teacher_phone', 'student_phone', 'relation_type', 'status']
 
     def validate(self, attrs):
         actor = self.context['request'].user
-        teacher = attrs.get('teacher') or (self.instance.teacher if self.instance else None)
-        student = attrs.get('student') or (self.instance.student if self.instance else None)
+        creating = self.instance is None
+        t_phone = (attrs.pop('teacher_phone', None) or '').strip()
+        s_phone = (attrs.pop('student_phone', None) or '').strip()
+
+        if creating and (not t_phone or not s_phone):
+            raise AppError('CMS_VALIDATION_ERROR', '带教老师手机号和学生手机号均必填', status_code=400)
+
+        # 按手机号解析（带教老师须 doctor、学生须 student）；编辑时未传则沿用原值
+        teacher = self.instance.teacher if self.instance else None
+        student = self.instance.student if self.instance else None
+        if t_phone:
+            teacher = User.objects.filter(phone=t_phone, role_type='doctor').first()
+            if teacher is None:
+                raise AppError('CMS_REL_TEACHER_NOT_FOUND', f'带教老师不存在或非医生：{t_phone}', status_code=400)
+        if s_phone:
+            student = User.objects.filter(phone=s_phone, role_type='student').first()
+            if student is None:
+                raise AppError('CMS_REL_STUDENT_NOT_FOUND', f'学生不存在或非学生：{s_phone}', status_code=400)
         if teacher is None or student is None:
-            raise AppError('CMS_VALIDATION_ERROR', '带教医生和学生均必填', status_code=400)
+            raise AppError('CMS_VALIDATION_ERROR', '带教老师和学生均必填', status_code=400)
 
         if not is_super(actor):
             if not actor.institution_id:
                 raise AppError('CMS_NO_INSTITUTION', '当前医院管理员无所属机构', status_code=403)
             if teacher.institution_id != actor.institution_id:
-                raise AppError('CMS_REL_SCOPE_FORBIDDEN', '带教医生不属于本院', status_code=403)
+                raise AppError('CMS_REL_SCOPE_FORBIDDEN', '带教老师不属于本院', status_code=403)
             if student.institution_id != actor.institution_id:
                 raise AppError('CMS_REL_SCOPE_FORBIDDEN', '学生不属于本院', status_code=403)
 
@@ -62,6 +79,9 @@ class CmsRelationWriteSerializer(serializers.ModelSerializer):
             dup = dup.exclude(pk=self.instance.pk)
         if dup.exists():
             raise AppError('CMS_REL_EXISTS', '该师生关系已存在', status_code=400)
+
+        attrs['teacher'] = teacher
+        attrs['student'] = student
         return attrs
 
 
diff --git a/test/test_cms_relation.py b/test/test_cms_relation.py
index 0d564ca..e90be82 100644
--- a/test/test_cms_relation.py
+++ b/test/test_cms_relation.py
@@ -46,7 +46,7 @@ class CmsRelationTest(CacheTestCase):
         self.assertEqual(stu_client.get(REL_URL).status_code, 403)
 
     def test_create_and_list(self):
-        resp = self.client.post(REL_URL, {'teacher': self.doc.id, 'student': self.stu.id})
+        resp = self.client.post(REL_URL, {'teacher_phone': '13932000002', 'student_phone': '13932000003'})
         self.assertEqual(resp.status_code, 201, resp.content)
         self.assertEqual(resp.json()['teacher_phone'], '13932000002')
         self.assertEqual(resp.json()['student_phone'], '13932000003')
@@ -55,19 +55,25 @@ class CmsRelationTest(CacheTestCase):
         self.assertEqual(resp.status_code, 200)
         self.assertEqual(len(resp.json()['results']), 1)
 
+    def test_create_missing_phone_400(self):
+        resp = self.client.post(REL_URL, {'teacher_phone': '13932000002'})
+        self.assertEqual(resp.status_code, 400, resp.content)
+        self.assertEqual(resp.json()['code'], 'CMS_VALIDATION_ERROR')
+
     def test_create_duplicate(self):
-        self.client.post(REL_URL, {'teacher': self.doc.id, 'student': self.stu.id})
-        resp = self.client.post(REL_URL, {'teacher': self.doc.id, 'student': self.stu.id})
+        self.client.post(REL_URL, {'teacher_phone': '13932000002', 'student_phone': '13932000003'})
+        resp = self.client.post(REL_URL, {'teacher_phone': '13932000002', 'student_phone': '13932000003'})
         self.assertEqual(resp.status_code, 400, resp.content)
         self.assertEqual(resp.json()['code'], 'CMS_REL_EXISTS')
 
     def test_teacher_must_be_doctor(self):
-        # 用学生当 teacher → 无效 pk
-        resp = self.client.post(REL_URL, {'teacher': self.stu.id, 'student': self.stu.id})
+        # 用学生手机号当带教老师 → 解析不到 doctor
+        resp = self.client.post(REL_URL, {'teacher_phone': '13932000003', 'student_phone': '13932000003'})
         self.assertEqual(resp.status_code, 400, resp.content)
+        self.assertEqual(resp.json()['code'], 'CMS_REL_TEACHER_NOT_FOUND')
 
     def test_scope_other_institution_student_rejected(self):
-        resp = self.client.post(REL_URL, {'teacher': self.doc.id, 'student': self.other_stu.id})
+        resp = self.client.post(REL_URL, {'teacher_phone': '13932000002', 'student_phone': '13932000004'})
         self.assertEqual(resp.status_code, 403, resp.content)
         self.assertEqual(resp.json()['code'], 'CMS_REL_SCOPE_FORBIDDEN')