diff --git a/backend/controllers/account_group.go b/backend/controllers/account_group.go
index a5400d0c..15845feb 100644
--- a/backend/controllers/account_group.go
+++ b/backend/controllers/account_group.go
@@ -49,6 +49,14 @@ func requireAccountGroupManagement(ctx *context.Context, w http.ResponseWriter)
 	return true
 }
 
+func requireAccountGroupMembershipManagement(ctx *context.Context, w http.ResponseWriter) bool {
+	if err := authorizeCapability(ctx, access.CapabilityAccountGroupMemberManage, "", false); err != nil {
+		writeUserAuthorizationError(w, err, "无权管理账号所属分组")
+		return false
+	}
+	return true
+}
+
 func SaveAccountGroup(ctx *context.Context, w http.ResponseWriter, req *http.Request) {
 	if !requireAccountGroupManagement(ctx, w) {
 		return
@@ -91,7 +99,7 @@ func SaveAccountGroup(ctx *context.Context, w http.ResponseWriter, req *http.Req
 }
 
 func SetAccountGroupMembership(ctx *context.Context, w http.ResponseWriter, req *http.Request) {
-	if !requireAccountGroupManagement(ctx, w) {
+	if !requireAccountGroupMembershipManagement(ctx, w) {
 		return
 	}
 	var input struct {
@@ -117,7 +125,13 @@ func SetAccountGroupMembership(ctx *context.Context, w http.ResponseWriter, req
 		writeAccountGroupError(w, accountgroup.ErrConflict)
 		return
 	}
-	if err := accountgroup.SetMembership(db.Instance, user, input.GroupIDs, accountWriteGuard(ctx, user)); err != nil {
+	if err := accountgroup.SetMembership(
+		db.Instance,
+		user,
+		input.GroupIDs,
+		accountWriteGuard(ctx, user),
+		accountgroup.MembershipScopeGuard(ctx.UserID, ctx.EffectiveRole(), input.GroupIDs),
+	); err != nil {
 		writeAccountGroupError(w, err)
 		return
 	}
diff --git a/backend/controllers/user.go b/backend/controllers/user.go
index d0377d21..9166c5ec 100644
--- a/backend/controllers/user.go
+++ b/backend/controllers/user.go
@@ -99,7 +99,7 @@ func CreateUser(ctx *context.Context, w http.ResponseWriter, req *http.Request)
 		groupIDs = *reqData.GroupIDs
 	}
 	if len(groupIDs) > 0 && (len(groupIDs) != 1 || groupIDs[0] != 0) {
-		if !requireAccountGroupManagement(ctx, w) {
+		if !requireAccountGroupMembershipManagement(ctx, w) {
 			return
 		}
 	}
@@ -378,7 +378,7 @@ func EditUser(ctx *context.Context, w http.ResponseWriter, req *http.Request) {
 	targetRole := user.EffectiveRole()
 	writeGuard := accountWriteGuard(ctx, user)
 	if reqData.GroupIDs != nil {
-		if !requireAccountGroupManagement(ctx, w) {
+		if !requireAccountGroupMembershipManagement(ctx, w) {
 			return
 		}
 		if reqData.MembershipVersion < 1 || reqData.MembershipVersion != user.SecurityVersion {
@@ -492,6 +492,13 @@ func EditUser(ctx *context.Context, w http.ResponseWriter, req *http.Request) {
 		writeAccountGroupError(w, err)
 		return
 	}
+	if reqData.GroupIDs != nil {
+		if err := accountgroup.CheckWrite(tx, accountgroup.MembershipScopeGuard(ctx.UserID, ctx.EffectiveRole(), *reqData.GroupIDs)); err != nil {
+			_ = tx.Rollback()
+			writeAccountGroupError(w, err)
+			return
+		}
+	}
 	if reqData.Password != "" {
 		updateColumns = append(updateColumns, "password", "must_change_password", "password_changed_at")
 	}
diff --git a/backend/services/access/capability.go b/backend/services/access/capability.go
index 7efffae4..c077b477 100644
--- a/backend/services/access/capability.go
+++ b/backend/services/access/capability.go
@@ -28,6 +28,7 @@ const (
 	CapabilityNotificationManage Capability = "notification.manage"
 	CapabilityNotificationReveal Capability = "notification.reveal"
 	CapabilityAccountGroupManage Capability = "account_group.manage"
+	CapabilityAccountGroupMemberManage Capability = "account_group.member_manage"
 )
 
 type Policy struct {
@@ -41,6 +42,7 @@ type Policy struct {
 var policies = map[Capability]Policy{
 	CapabilityNotificationReveal: {Capability: CapabilityNotificationReveal, HighRisk: true, RequiresTarget: true},
 	CapabilityAccountGroupManage: {Capability: CapabilityAccountGroupManage, HighRisk: true, RequiresRecentAuth: true},
+	CapabilityAccountGroupMemberManage: {Capability: CapabilityAccountGroupMemberManage, HighRisk: true, RequiresRecentAuth: true},
 	CapabilityNotificationManage: {Capability: CapabilityNotificationManage, HighRisk: true, RequiresRecentAuth: true, RequiresRecoveryCode: true, RequiresTarget: true},
 	CapabilityConfigRead:         {Capability: CapabilityConfigRead},
 	CapabilityConfigWriteGlobal:  {Capability: CapabilityConfigWriteGlobal, HighRisk: true, RequiresRecentAuth: true, RequiresRecoveryCode: true},
@@ -70,6 +72,7 @@ var grants = map[Role]map[Capability]struct{}{
 	RoleSuperAdmin: grant(
 		CapabilityNotificationReveal,
 		CapabilityAccountGroupManage,
+		CapabilityAccountGroupMemberManage,
 		CapabilityNotificationManage,
 		CapabilityPluginReadGlobal, CapabilityUserCreate, CapabilityProfileWriteOwn,
 		CapabilityConfigRead, CapabilityConfigWriteGlobal, CapabilityConfigRollback,
@@ -81,6 +84,7 @@ var grants = map[Role]map[Capability]struct{}{
 	),
 	RoleAdmin: grant(
 		CapabilityNotificationReveal,
+		CapabilityAccountGroupMemberManage,
 		CapabilityNotificationManage,
 		CapabilityPluginReadGlobal, CapabilityPluginRead, CapabilityPluginWriteGlobal, CapabilityProfileWriteOwn,
 		CapabilityPluginWriteAnyUser, CapabilityPluginWriteOwn, CapabilityUserRead,
diff --git a/backend/services/access/catalog.go b/backend/services/access/catalog.go
index 1d570419..cf94edb0 100644
--- a/backend/services/access/catalog.go
+++ b/backend/services/access/catalog.go
@@ -14,9 +14,9 @@ var managementEndpoints = []Endpoint{
 	{Method: "POST", Path: "/api/system/notification/authorization", Capability: CapabilityNotificationManage},
 	{Method: "POST", Path: "/api/system/notification/credential", Capability: CapabilityNotificationManage},
 	{Method: "POST", Path: "/api/v1/user/groups/save", Capability: CapabilityAccountGroupManage},
-	{Method: "POST", Path: "/api/v1/user/groups/membership", Capability: CapabilityAccountGroupManage},
+	{Method: "POST", Path: "/api/v1/user/groups/membership", Capability: CapabilityAccountGroupMemberManage},
 	{Method: "POST", Path: "/api/user/groups/save", Capability: CapabilityAccountGroupManage},
-	{Method: "POST", Path: "/api/user/groups/membership", Capability: CapabilityAccountGroupManage},
+	{Method: "POST", Path: "/api/user/groups/membership", Capability: CapabilityAccountGroupMemberManage},
 	{Method: "POST", Path: "/api/v1/system/notification/authorization", Capability: CapabilityNotificationManage},
 	{Method: "POST", Path: "/api/v1/system/notification/credential", Capability: CapabilityNotificationManage},
 	{Method: "POST", Path: "/api/settings/modify_password", Capability: CapabilityPasswordChangeOwn},
diff --git a/backend/services/accountgroup/service.go b/backend/services/accountgroup/service.go
index b4d9158a..2f684137 100644
--- a/backend/services/accountgroup/service.go
+++ b/backend/services/accountgroup/service.go
@@ -170,6 +170,38 @@ func ValidateMembership(tx *xorm.Session, role access.Role, input []int) ([]int,
 	return ids, nil
 }
 
+// MembershipScopeGuard 限制管理员只能把成员放入自己所属的分组。
+func MembershipScopeGuard(actorID int, role access.Role, input []int) WriteGuard {
+	return func(tx *xorm.Session) error {
+		if tx == nil || actorID <= 0 || !role.Valid() {
+			return ErrDenied
+		}
+		if role == access.RoleSuperAdmin {
+			return nil
+		}
+		if role != access.RoleAdmin {
+			return ErrDenied
+		}
+		allowedRows := make([]models.AccountGroupMember, 0)
+		if err := tx.Where("user_id = ?", actorID).Find(&allowedRows); err != nil {
+			return err
+		}
+		allowed := make(map[int]struct{}, len(allowedRows))
+		for _, row := range allowedRows {
+			allowed[row.GroupID] = struct{}{}
+		}
+		if len(allowed) == 0 {
+			allowed[0] = struct{}{}
+		}
+		for _, groupID := range input {
+			if _, ok := allowed[groupID]; !ok {
+				return ErrDenied
+			}
+		}
+		return nil
+	}
+}
+
 func ReplaceMembership(tx *xorm.Session, userID int, ids []int) error {
 	if _, err := tx.Where("user_id = ?", userID).Delete(&models.AccountGroupMember{}); err != nil {
 		return err
diff --git a/frontend/src/views/components/UserManagement/AccountGroups.js b/frontend/src/views/components/UserManagement/AccountGroups.js
index ef40dfc6..65c32efc 100644
--- a/frontend/src/views/components/UserManagement/AccountGroups.js
+++ b/frontend/src/views/components/UserManagement/AccountGroups.js
@@ -8,6 +8,7 @@ export function useAccountGroups(globalStatus, onMembershipSaved = () => {}) {
   const groupsLoading = ref(false)
   const groupsError = ref('')
   const canManageGroups = computed(() => globalStatus.hasCapability('account_group.manage'))
+  const canManageMembership = computed(() => globalStatus.hasCapability('account_group.member_manage'))
   const groupSaving = ref(false)
   const membershipVisible = ref(false)
   const membershipUser = ref(null)
@@ -128,7 +129,7 @@ export function useAccountGroups(globalStatus, onMembershipSaved = () => {}) {
   }
 
   const editMembership = (user, options = {}) => {
-    if (!canManageGroups.value || groupSaving.value) return
+    if (!canManageMembership.value || groupSaving.value) return
     membershipUser.value = { ...user, Role: options.role || user.Role }
     membershipSelection.value = [...(options.groupIDs || user.GroupIDs || [0])]
     applyMembershipDraft = options.onApply || null
@@ -137,7 +138,7 @@ export function useAccountGroups(globalStatus, onMembershipSaved = () => {}) {
   }
 
   const saveMembership = async () => {
-    if (!canManageGroups.value || groupSaving.value || !membershipUser.value) return
+    if (!canManageMembership.value || groupSaving.value || !membershipUser.value) return
     if (membershipSelection.value.length === 0) membershipSelection.value = [0]
     if (membershipSelection.value.length > membershipLimit.value) {
       ElMessage.error('普通用户只能选择一个分组，请重新选择')
@@ -174,7 +175,7 @@ export function useAccountGroups(globalStatus, onMembershipSaved = () => {}) {
   }
 
   return {
-    accountGroups, groupsLoading, groupsError, canManageGroups, groupSaving,
+    accountGroups, groupsLoading, groupsError, canManageGroups, canManageMembership, groupSaving,
     membershipVisible, membershipUser, membershipSelection, membershipLimit,
     membershipDraft, membershipSingleSelection,
     refreshGroups, loadGroup, toggleGroup, saveGroup, createMembershipGroup, editMembership, saveMembership
diff --git a/frontend/src/views/components/UserManagement/UserManagement.js b/frontend/src/views/components/UserManagement/UserManagement.js
index a4fa4c13..58023887 100644
--- a/frontend/src/views/components/UserManagement/UserManagement.js
+++ b/frontend/src/views/components/UserManagement/UserManagement.js
@@ -69,7 +69,7 @@ export function usePage() {
     const user = selectedUser.value
     if (!user && editModel.value !== 'create') return []
     return groups.accountGroups.value.filter(group =>
-      groups.canManageGroups.value
+      groups.canManageMembership.value
         ? editingGroupIDs.value.includes(group.id)
         : group.rows.some(member => member.ID === user.ID)
     )
@@ -243,7 +243,7 @@ export function usePage() {
       }
       if (creating || roleChanged.value) newData.role = editUserInfo.role
       if (creating || editUserInfo.password !== '') newData.password = editUserInfo.password
-      if (groups.canManageGroups.value && (creating || membershipChanged.value || roleChanged.value)) {
+      if (groups.canManageMembership.value && (creating || membershipChanged.value || roleChanged.value)) {
         if (editUserInfo.role !== 'admin' && editingGroupIDs.value.length !== 1) {
           throw new Error('普通用户只能属于一个分组，请在分组管理中选择一个分组')
         }