diff --git a/frontend/src/components/admin/user/UserAllowedGroupsModal.vue b/frontend/src/components/admin/user/UserAllowedGroupsModal.vue
index 6360680e7e..7486222572 100644
--- a/frontend/src/components/admin/user/UserAllowedGroupsModal.vue
+++ b/frontend/src/components/admin/user/UserAllowedGroupsModal.vue
@@ -188,7 +188,7 @@
     <template #footer>
       <div class="flex justify-end gap-3">
         <button @click="$emit('close')" class="btn btn-secondary px-5">{{ t('common.cancel') }}</button>
-        <button @click="handleSave" :disabled="submitting" class="btn btn-primary px-6">
+        <button @click="handleSave" :disabled="submitting || !loaded" class="btn btn-primary px-6">
           <svg v-if="submitting" class="-ml-1 mr-2 h-4 w-4 animate-spin" fill="none" viewBox="0 0 24 24">
             <circle class="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" stroke-width="4"></circle>
             <path class="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"></path>
@@ -228,6 +228,7 @@ const groups = ref<Group[]>([])
 const groupConfigs = ref<GroupRateConfig[]>([])
 const originalGroupRates = ref<Record<number, number>>({}) // 记录原始专属倍率，用于检测删除
 const loading = ref(false)
+const loaded = ref(false)
 const submitting = ref(false)
 const restrictPublicGroups = ref(false)
 
@@ -248,6 +249,7 @@ watch(
 )
 
 const load = async () => {
+  loaded.value = false
   loading.value = true
   try {
     const res = await adminAPI.groups.list(1, 1000)
@@ -274,6 +276,7 @@ const load = async () => {
       isSelected:
         g.is_exclusive || restrictPublicGroups.value ? userAllowedGroups.includes(g.id) : true,
     }))
+    loaded.value = true
   } catch (error) {
     console.error('Failed to load groups:', error)
   } finally {
@@ -318,7 +321,7 @@ const updateCustomRate = (groupId: number, value: string) => {
 }
 
 const handleSave = async () => {
-  if (!props.user) return
+  if (!props.user || !loaded.value) return
   submitting.value = true
 
   try {
diff --git a/frontend/src/components/admin/user/__tests__/UserAllowedGroupsModal.spec.ts b/frontend/src/components/admin/user/__tests__/UserAllowedGroupsModal.spec.ts
new file mode 100644
index 0000000000..82c545e10b
--- /dev/null
+++ b/frontend/src/components/admin/user/__tests__/UserAllowedGroupsModal.spec.ts
@@ -0,0 +1,71 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { enableAutoUnmount, flushPromises, mount } from '@vue/test-utils'
+import type { AdminUser } from '@/types'
+import UserAllowedGroupsModal from '../UserAllowedGroupsModal.vue'
+
+const mocks = vi.hoisted(() => ({ list: vi.fn(), update: vi.fn() }))
+vi.mock('@/api/admin', () => ({ adminAPI: { groups: { list: mocks.list }, users: { update: mocks.update } } }))
+vi.mock('@/stores/app', () => ({ useAppStore: () => ({ showSuccess: vi.fn(), showError: vi.fn() }) }))
+vi.mock('vue-i18n', () => ({ useI18n: () => ({ t: (key: string) => key }) }))
+enableAutoUnmount(afterEach)
+afterEach(() => vi.restoreAllMocks())
+const response = { items: [{ id: 7, name: 'Exclusive', platform: 'openai', is_exclusive: true, subscription_type: 'standard', status: 'active', rate_multiplier: 1 }] }
+beforeEach(() => {
+  vi.clearAllMocks()
+  vi.spyOn(console, 'error').mockImplementation(() => {})
+  mocks.list.mockResolvedValue(response)
+  mocks.update.mockResolvedValue(undefined)
+})
+async function openDialog() {
+  const wrapper = mount(UserAllowedGroupsModal, {
+    props: { show: false, user: { id: 1, email: 'user@example.com', allowed_groups: [7], group_rates: { 7: 0.5 } } as AdminUser },
+    global: { stubs: { BaseDialog: { props: ['show'], template: '<div v-if="show"><slot /><slot name="footer" /></div>' }, PlatformIcon: true } }
+  })
+  await wrapper.setProps({ show: true })
+  return wrapper
+}
+
+describe('UserAllowedGroupsModal load readiness', () => {
+  it('cannot save an empty configuration while groups are loading', async () => {
+    let resolve!: (value: typeof response) => void
+    mocks.list.mockReturnValueOnce(new Promise(res => { resolve = res }))
+    const wrapper = await openDialog()
+    const save = wrapper.get('button.btn-primary')
+    expect(save.attributes('disabled')).toBeDefined()
+    await save.trigger('click')
+    expect(mocks.update).not.toHaveBeenCalled()
+    resolve(response)
+    await flushPromises()
+    expect(save.attributes('disabled')).toBeUndefined()
+  })
+
+  it('cannot save after loading fails', async () => {
+    mocks.list.mockRejectedValueOnce(new Error('Offline'))
+    const wrapper = await openDialog()
+    await flushPromises()
+    const save = wrapper.get('button.btn-primary')
+    expect(save.attributes('disabled')).toBeDefined()
+    await save.trigger('click')
+    expect(mocks.update).not.toHaveBeenCalled()
+  })
+
+  it('does not reuse a previous successful load after reopening fails', async () => {
+    const wrapper = await openDialog()
+    await flushPromises()
+    await wrapper.setProps({ show: false })
+    mocks.list.mockRejectedValueOnce(new Error('Offline'))
+    await wrapper.setProps({ show: true })
+    await flushPromises()
+    expect(wrapper.get('button.btn-primary').attributes('disabled')).toBeDefined()
+    expect(mocks.update).not.toHaveBeenCalled()
+  })
+
+  it('preserves existing grants and rates on a successful save', async () => {
+    const wrapper = await openDialog()
+    await flushPromises()
+    await wrapper.get('button.btn-primary').trigger('click')
+    await flushPromises()
+    expect(mocks.update).toHaveBeenCalledWith(1, { allowed_groups: [7], restrict_public_groups: false, group_rates: { 7: 0.5 } })
+    expect(wrapper.emitted('success')).toHaveLength(1)
+  })
+})