diff --git a/pjcloud-upms/pjcloud-upms-biz/src/main/java/com/bsd/pjcloud/admin/mapper/user/SysUserRelationMapper.java b/pjcloud-upms/pjcloud-upms-biz/src/main/java/com/bsd/pjcloud/admin/mapper/user/SysUserRelationMapper.java
index 6260e5617..67453f6d0 100755
--- a/pjcloud-upms/pjcloud-upms-biz/src/main/java/com/bsd/pjcloud/admin/mapper/user/SysUserRelationMapper.java
+++ b/pjcloud-upms/pjcloud-upms-biz/src/main/java/com/bsd/pjcloud/admin/mapper/user/SysUserRelationMapper.java
@@ -3,8 +3,32 @@ package com.bsd.pjcloud.admin.mapper.user;
 import com.bsd.pjcloud.admin.api.entity.user.SysUserRelationEntity;
 import com.bsd.pjcloud.common.data.datascope.PjcloudBaseMapper;
 import org.apache.ibatis.annotations.Mapper;
+import org.apache.ibatis.annotations.Param;
 
+/**
+ * 用户关系数据访问层，负责关系记录的常规持久化及逻辑删除后的安全恢复。
+ */
 @Mapper
 public interface SysUserRelationMapper extends PjcloudBaseMapper<SysUserRelationEntity> {
 
-}
\ No newline at end of file
+    /**
+     * 按唯一键查询已逻辑删除的关系记录，查询范围由租户拦截器限制为当前租户。
+     *
+     * @param subjectUserId 关系主语用户 ID
+     * @param objectUserId 关系对象用户 ID
+     * @param relationTypeId 关系类型 ID
+     * @return 已删除的关系记录，仅返回关系 ID；不存在时返回空
+     */
+    SysUserRelationEntity selectDeletedByUniqueKey(@Param("subjectUserId") Long subjectUserId,
+                                                   @Param("objectUserId") Long objectUserId,
+                                                   @Param("relationTypeId") Long relationTypeId);
+
+    /**
+     * 恢复指定的已删除关系，并使用本次创建请求覆盖关系时效和备注信息。
+     *
+     * @param relation 包含原关系 ID 以及本次创建请求数据的关系实体
+     * @return 实际恢复的记录数，返回 0 表示记录已被并发恢复或不存在
+     */
+    int restoreDeletedRelation(@Param("relation") SysUserRelationEntity relation);
+
+}
diff --git a/pjcloud-upms/pjcloud-upms-biz/src/main/java/com/bsd/pjcloud/admin/service/impl/user/SysUserRelationServiceImpl.java b/pjcloud-upms/pjcloud-upms-biz/src/main/java/com/bsd/pjcloud/admin/service/impl/user/SysUserRelationServiceImpl.java
index fa2fe57f4..b8c86fbdf 100755
--- a/pjcloud-upms/pjcloud-upms-biz/src/main/java/com/bsd/pjcloud/admin/service/impl/user/SysUserRelationServiceImpl.java
+++ b/pjcloud-upms/pjcloud-upms-biz/src/main/java/com/bsd/pjcloud/admin/service/impl/user/SysUserRelationServiceImpl.java
@@ -26,6 +26,7 @@ import com.bsd.pjcloud.common.core.exception.ErrorCodes;
 import com.bsd.pjcloud.common.core.util.MsgUtils;
 import lombok.RequiredArgsConstructor;
 import org.springframework.beans.BeanUtils;
+import org.springframework.dao.DuplicateKeyException;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -482,6 +483,12 @@ public class SysUserRelationServiceImpl extends ServiceImpl<SysUserRelationMappe
         return newUserId;
     }
 
+    /**
+     * 为两个已有用户建立关系；若相同唯一键的历史关系已逻辑删除，则恢复原记录而不是重复插入。
+     *
+     * @param dto 关系双方、关系类型、有效期及备注
+     * @return 新增或恢复后的关系 ID
+     */
     @Override
     @Transactional(rollbackFor = Exception.class)
     public Long createRelation(SysUserRelationCreateDto dto) {
@@ -491,10 +498,38 @@ public class SysUserRelationServiceImpl extends ServiceImpl<SysUserRelationMappe
 
         SysUserRelationEntity relation = new SysUserRelationEntity();
         BeanUtils.copyProperties(dto, relation);
-        save(relation);
+        Long relationId = saveOrRestoreRelation(relation);
         if (isGuardianWardRelationType(relationType)) {
+            // 监护关系主语即监护人，关系保存后直接用其 sys_user.phone 重算学生 guardian_phones。
             syncStudentGuardianPhones(List.of(relation.getObjectUserId()));
         }
+        return relationId;
+    }
+
+    /**
+     * 新增关系或恢复相同唯一键下的已删除关系，兼容唯一索引不包含删除标记的历史表结构。
+     *
+     * @param relation 本次待建立的关系数据
+     * @return 新增或恢复后的关系 ID
+     */
+    private Long saveOrRestoreRelation(SysUserRelationEntity relation) {
+        SysUserRelationEntity deletedRelation = baseMapper.selectDeletedByUniqueKey(
+                relation.getSubjectUserId(), relation.getObjectUserId(), relation.getRelationTypeId());
+        if (deletedRelation != null) {
+            relation.setRelationId(deletedRelation.getRelationId());
+            if (baseMapper.restoreDeletedRelation(relation) != 1) {
+                throw new RuntimeException("所选用户之间已存在该类型的关系");
+            }
+            return relation.getRelationId();
+        }
+        try {
+            if (!save(relation)) {
+                throw new RuntimeException("用户关系建立失败");
+            }
+        } catch (DuplicateKeyException exception) {
+            // 并发请求可能同时通过前置校验，最终仍以数据库唯一索引兜底并返回可读的业务提示。
+            throw new RuntimeException("所选用户之间已存在该类型的关系", exception);
+        }
         return relation.getRelationId();
     }
 
@@ -568,6 +603,14 @@ public class SysUserRelationServiceImpl extends ServiceImpl<SysUserRelationMappe
         }
     }
 
+    /**
+     * 校验关系双方及关系类型；监护人手机号由关系保存后的同步流程直接从用户表读取。
+     *
+     * @param subjectUserId 关系主语用户 ID
+     * @param objectUserId 关系对象用户 ID
+     * @param relationTypeId 关系类型 ID
+     * @return 已校验且当前启用的关系类型
+     */
     private SysUserRelationTypeEntity validateRelation(Long subjectUserId, Long objectUserId, Long relationTypeId) {
         if (Objects.equals(subjectUserId, objectUserId)) {
             throw new RuntimeException("不能与自己建立用户关系");
@@ -576,11 +619,7 @@ public class SysUserRelationServiceImpl extends ServiceImpl<SysUserRelationMappe
         if (subjectUser == null) {
             throw new RuntimeException("关系主语用户不存在");
         }
-        SysUserRelationTypeEntity relationType = validateObjectUserAndRelationType(objectUserId, relationTypeId);
-        if (isGuardianWardRelationType(relationType) && StrUtil.isBlank(subjectUser.getPhone())) {
-            throw new RuntimeException("监护人手机号不能为空");
-        }
-        return relationType;
+        return validateObjectUserAndRelationType(objectUserId, relationTypeId);
     }
 
     private SysUserRelationTypeEntity validateObjectUserAndRelationType(Long objectUserId, Long relationTypeId) {
diff --git a/pjcloud-upms/pjcloud-upms-biz/src/main/resources/mapper/user/SysUserRelationMapper.xml b/pjcloud-upms/pjcloud-upms-biz/src/main/resources/mapper/user/SysUserRelationMapper.xml
index 3eb2e58cd..2ffb87f00 100755
--- a/pjcloud-upms/pjcloud-upms-biz/src/main/resources/mapper/user/SysUserRelationMapper.xml
+++ b/pjcloud-upms/pjcloud-upms-biz/src/main/resources/mapper/user/SysUserRelationMapper.xml
@@ -3,5 +3,27 @@
 
 <mapper namespace="com.bsd.pjcloud.admin.mapper.user.SysUserRelationMapper">
 
+    <!-- 唯一索引不包含删除标记，重新建立关系时需要先定位当前租户内的历史删除记录。 -->
+    <select id="selectDeletedByUniqueKey"
+            resultType="com.bsd.pjcloud.admin.api.entity.user.SysUserRelationEntity">
+        SELECT relation_id AS relationId
+        FROM sys_user_relation
+        WHERE subject_user_id = #{subjectUserId}
+          AND object_user_id = #{objectUserId}
+          AND relation_type_id = #{relationTypeId}
+          AND del_flag = '1'
+        LIMIT 1
+    </select>
 
-</mapper>
\ No newline at end of file
+    <!-- 恢复历史关系时覆盖本次提交的有效期和备注，并通过删除标记防止并发重复恢复。 -->
+    <update id="restoreDeletedRelation">
+        UPDATE sys_user_relation
+        SET effective_time = #{relation.effectiveTime},
+            expire_time = #{relation.expireTime},
+            remark = #{relation.remark},
+            del_flag = '0',
+            update_time = CURRENT_TIMESTAMP
+        WHERE relation_id = #{relation.relationId}
+          AND del_flag = '1'
+    </update>
+</mapper>
diff --git a/pjcloud-upms/pjcloud-upms-biz/src/test/java/com/bsd/pjcloud/admin/service/impl/user/SysUserRelationServiceImplTest.java b/pjcloud-upms/pjcloud-upms-biz/src/test/java/com/bsd/pjcloud/admin/service/impl/user/SysUserRelationServiceImplTest.java
index 3f02e5e1a..a1cfc2b72 100644
--- a/pjcloud-upms/pjcloud-upms-biz/src/test/java/com/bsd/pjcloud/admin/service/impl/user/SysUserRelationServiceImplTest.java
+++ b/pjcloud-upms/pjcloud-upms-biz/src/test/java/com/bsd/pjcloud/admin/service/impl/user/SysUserRelationServiceImplTest.java
@@ -1,14 +1,18 @@
 package com.bsd.pjcloud.admin.service.impl.user;
 
 import com.baomidou.mybatisplus.core.conditions.Wrapper;
+import com.bsd.pjcloud.admin.api.dto.user.SysUserRelationCreateDto;
 import com.bsd.pjcloud.admin.api.entity.SysUser;
 import com.bsd.pjcloud.admin.api.entity.user.SysUserRelationEntity;
 import com.bsd.pjcloud.admin.api.entity.user.SysUserRelationTypeEntity;
 import com.bsd.pjcloud.admin.api.vo.user.SysUserRelationGraphVo;
+import com.bsd.pjcloud.admin.mapper.user.SysUserRelationMapper;
 import com.bsd.pjcloud.admin.service.SysUserRelationTypeService;
 import com.bsd.pjcloud.admin.service.SysUserService;
 import com.bsd.pjcloud.admin.service.SysUserStudentService;
+import com.bsd.pjcloud.common.core.constant.CommonConstants;
 import org.junit.jupiter.api.Test;
+import org.springframework.test.util.ReflectionTestUtils;
 
 import java.util.List;
 import java.util.Set;
@@ -19,7 +23,9 @@ import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -164,6 +170,43 @@ class SysUserRelationServiceImplTest {
         verify(studentService).updateGuardianPhones(FIRST_WARD_USER_ID, null);
     }
 
+    /**
+     * 验证相同关系曾被逻辑删除时，创建接口恢复原记录而不是再次插入触发唯一索引冲突。
+     */
+    @Test
+    void shouldRestoreDeletedRelationInsteadOfInsertingDuplicate() {
+        SysUserService sysUserService = mock(SysUserService.class);
+        SysUserRelationTypeService relationTypeService = mock(SysUserRelationTypeService.class);
+        SysUserRelationMapper relationMapper = mock(SysUserRelationMapper.class);
+        SysUserRelationServiceImpl service = spy(new SysUserRelationServiceImpl(
+                sysUserService, relationTypeService, mock(SysUserStudentService.class)));
+        ReflectionTestUtils.setField(service, "baseMapper", relationMapper);
+
+        SysUserRelationTypeEntity relationType = createGuardianRelationType();
+        relationType.setStatus(CommonConstants.STATUS_NORMAL);
+        when(sysUserService.getById(GUARDIAN_USER_ID)).thenReturn(createUser(GUARDIAN_USER_ID, "监护人"));
+        when(sysUserService.getById(SECOND_WARD_USER_ID)).thenReturn(createUser(SECOND_WARD_USER_ID, "被监护人二"));
+        when(relationTypeService.getById(RELATION_TYPE_ID)).thenReturn(relationType);
+        doReturn(false).when(service).exists(org.mockito.ArgumentMatchers.<Wrapper<SysUserRelationEntity>>any());
+        doNothing().when(service).syncStudentGuardianPhones(any());
+
+        SysUserRelationEntity deletedRelation = createRelation(99L, SECOND_WARD_USER_ID);
+        when(relationMapper.selectDeletedByUniqueKey(GUARDIAN_USER_ID, SECOND_WARD_USER_ID, RELATION_TYPE_ID))
+                .thenReturn(deletedRelation);
+        when(relationMapper.restoreDeletedRelation(any())).thenReturn(1);
+        SysUserRelationCreateDto dto = new SysUserRelationCreateDto();
+        dto.setSubjectUserId(GUARDIAN_USER_ID);
+        dto.setObjectUserId(SECOND_WARD_USER_ID);
+        dto.setRelationTypeId(RELATION_TYPE_ID);
+
+        Long relationId = service.createRelation(dto);
+
+        assertEquals(99L, relationId);
+        verify(relationMapper).restoreDeletedRelation(any());
+        verify(relationMapper, never()).insert(any());
+        verify(service).syncStudentGuardianPhones(List.of(SECOND_WARD_USER_ID));
+    }
+
     private SysUserRelationEntity createRelation(Long relationId, Long wardUserId) {
         SysUserRelationEntity relation = new SysUserRelationEntity();
         relation.setRelationId(relationId);