diff --git a/frontend/src/api/auth.ts b/frontend/src/api/auth.ts
index 6a2feb87..6c877d76 100644
--- a/frontend/src/api/auth.ts
+++ b/frontend/src/api/auth.ts
@@ -349,6 +349,61 @@ export async function getPublicSettings(): Promise<PublicSettings> {
   return data
 }
 
+export type WeChatOAuthMode = 'open' | 'mp'
+export type WeChatOAuthUnavailableReason =
+  | 'not_configured'
+  | 'external_browser_required'
+  | 'wechat_browser_required'
+
+export interface ResolvedWeChatOAuthStart {
+  mode: WeChatOAuthMode | null
+  openEnabled: boolean
+  mpEnabled: boolean
+  isWeChatBrowser: boolean
+  unavailableReason: WeChatOAuthUnavailableReason | null
+}
+
+type WeChatOAuthPublicSettings = {
+  wechat_oauth_enabled?: boolean
+  wechat_oauth_open_enabled?: boolean
+  wechat_oauth_mp_enabled?: boolean
+}
+
+export function resolveWeChatOAuthStart(
+  settings: WeChatOAuthPublicSettings | null | undefined,
+  userAgent?: string
+): ResolvedWeChatOAuthStart {
+  const normalizedUserAgent = (userAgent
+    ?? (typeof navigator !== 'undefined' ? navigator.userAgent : '')
+    ?? '').trim()
+  const isWeChatBrowser = /MicroMessenger/i.test(normalizedUserAgent)
+  const legacyEnabled = settings?.wechat_oauth_enabled ?? false
+  const openEnabled = typeof settings?.wechat_oauth_open_enabled === 'boolean'
+    ? settings.wechat_oauth_open_enabled
+    : legacyEnabled
+  const mpEnabled = typeof settings?.wechat_oauth_mp_enabled === 'boolean'
+    ? settings.wechat_oauth_mp_enabled
+    : legacyEnabled
+
+  if (isWeChatBrowser) {
+    if (mpEnabled) {
+      return { mode: 'mp', openEnabled, mpEnabled, isWeChatBrowser, unavailableReason: null }
+    }
+    if (openEnabled) {
+      return { mode: null, openEnabled, mpEnabled, isWeChatBrowser, unavailableReason: 'external_browser_required' }
+    }
+    return { mode: null, openEnabled, mpEnabled, isWeChatBrowser, unavailableReason: 'not_configured' }
+  }
+
+  if (openEnabled) {
+    return { mode: 'open', openEnabled, mpEnabled, isWeChatBrowser, unavailableReason: null }
+  }
+  if (mpEnabled) {
+    return { mode: null, openEnabled, mpEnabled, isWeChatBrowser, unavailableReason: 'wechat_browser_required' }
+  }
+  return { mode: null, openEnabled, mpEnabled, isWeChatBrowser, unavailableReason: 'not_configured' }
+}
+
 /**
  * Send verification code to email
  * @param request - Email and optional Turnstile token
diff --git a/frontend/src/components/auth/WechatOAuthSection.vue b/frontend/src/components/auth/WechatOAuthSection.vue
index 94e20222..01bbd180 100644
--- a/frontend/src/components/auth/WechatOAuthSection.vue
+++ b/frontend/src/components/auth/WechatOAuthSection.vue
@@ -1,6 +1,6 @@
 <template>
   <div class="space-y-4">
-    <button type="button" :disabled="disabled" class="btn btn-secondary w-full" @click="startLogin">
+    <button type="button" :disabled="buttonDisabled" class="btn btn-secondary w-full" @click="startLogin">
       <span
         class="mr-2 inline-flex h-5 w-5 items-center justify-center rounded-full bg-green-100 text-xs font-semibold text-green-700 dark:bg-green-900/30 dark:text-green-300"
       >
@@ -9,6 +9,14 @@
       {{ t('auth.oidc.signIn', { providerName }) }}
     </button>
 
+    <p
+      v-if="disabledHint"
+      data-testid="wechat-oauth-hint"
+      class="text-sm text-amber-600 dark:text-amber-400"
+    >
+      {{ disabledHint }}
+    </p>
+
     <div v-if="showDivider" class="flex items-center gap-3">
       <div class="h-px flex-1 bg-gray-200 dark:bg-dark-700"></div>
       <span class="text-xs text-gray-500 dark:text-dark-400">
@@ -20,33 +28,69 @@
 </template>
 
 <script setup lang="ts">
+import { computed, onMounted } from 'vue'
 import { useRoute } from 'vue-router'
 import { useI18n } from 'vue-i18n'
+import { resolveWeChatOAuthStart } from '@/api/auth'
+import { useAppStore } from '@/stores'
 
-withDefaults(defineProps<{
+const props = withDefaults(defineProps<{
   disabled?: boolean
   showDivider?: boolean
 }>(), {
   showDivider: true,
 })
 
+const appStore = useAppStore()
 const route = useRoute()
-const { t } = useI18n()
-
+const { locale, t } = useI18n()
 const providerName = 'WeChat'
 
-function resolveWeChatOAuthMode(): 'open' | 'mp' {
-  if (typeof navigator === 'undefined') {
-    return 'open'
+const resolvedStart = computed(() => resolveWeChatOAuthStart(appStore.cachedPublicSettings))
+const buttonDisabled = computed(() => props.disabled || resolvedStart.value.mode === null)
+const disabledHint = computed(() => {
+  if (props.disabled) {
+    return ''
   }
-  return /MicroMessenger/i.test(navigator.userAgent) ? 'mp' : 'open'
+  switch (resolvedStart.value.unavailableReason) {
+    case 'external_browser_required':
+      return localizeWeChatHint(
+        '当前仅配置网站微信登录，请在系统浏览器中打开此页面后再继续。',
+        'This site only has WeChat website login configured. Open this page in your browser to continue.',
+      )
+    case 'wechat_browser_required':
+      return localizeWeChatHint(
+        '当前仅配置微信内登录，请在微信中打开此页面后再继续。',
+        'This site only has WeChat in-app login configured. Open this page inside WeChat to continue.',
+      )
+    case 'not_configured':
+      return localizeWeChatHint(
+        '管理员尚未配置微信登录。',
+        'WeChat sign-in is not configured yet.',
+      )
+    default:
+      return ''
+  }
+})
+
+function localizeWeChatHint(zh: string, en: string): string {
+  return locale.value.toLowerCase().startsWith('zh') ? zh : en
 }
 
+onMounted(() => {
+  if (!appStore.cachedPublicSettings && !appStore.publicSettingsLoaded) {
+    appStore.fetchPublicSettings()
+  }
+})
+
 function startLogin(): void {
+  if (buttonDisabled.value || !resolvedStart.value.mode) {
+    return
+  }
   const redirectTo = (route.query.redirect as string) || '/dashboard'
   const apiBase = (import.meta.env.VITE_API_BASE_URL as string | undefined) || '/api/v1'
   const normalized = apiBase.replace(/\/$/, '')
-  const mode = resolveWeChatOAuthMode()
+  const mode = resolvedStart.value.mode
   const startURL = `${normalized}/auth/oauth/wechat/start?mode=${mode}&redirect=${encodeURIComponent(redirectTo)}`
   window.location.href = startURL
 }
diff --git a/frontend/src/components/auth/__tests__/WechatOAuthSection.spec.ts b/frontend/src/components/auth/__tests__/WechatOAuthSection.spec.ts
index 810832a0..bf65f459 100644
--- a/frontend/src/components/auth/__tests__/WechatOAuthSection.spec.ts
+++ b/frontend/src/components/auth/__tests__/WechatOAuthSection.spec.ts
@@ -1,6 +1,9 @@
 import { mount } from '@vue/test-utils'
+import { createPinia, setActivePinia } from 'pinia'
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 import WechatOAuthSection from '@/components/auth/WechatOAuthSection.vue'
+import { useAppStore } from '@/stores'
+import type { PublicSettings } from '@/types'
 
 const routeState = vi.hoisted(() => ({
   query: {} as Record<string, unknown>,
@@ -10,26 +13,84 @@ const locationState = vi.hoisted(() => ({
   current: { href: 'http://localhost/login' } as { href: string },
 }))
 
+let pinia: ReturnType<typeof createPinia>
+
 vi.mock('vue-router', () => ({
   useRoute: () => routeState,
 }))
 
-vi.mock('vue-i18n', () => ({
-  useI18n: () => ({
-    t: (key: string, params?: Record<string, string>) => {
-      if (key === 'auth.oidc.signIn') {
-        return `Continue with ${params?.providerName ?? ''}`.trim()
-      }
-      if (key === 'auth.oauthOrContinue') {
-        return 'or continue'
-      }
-      return key
-    },
-  }),
-}))
+vi.mock('vue-i18n', async () => {
+  const actual = await vi.importActual<typeof import('vue-i18n')>('vue-i18n')
+  return {
+    ...actual,
+    useI18n: () => ({
+      locale: { value: 'en' },
+      t: (key: string, params?: Record<string, string>) => {
+        if (key === 'auth.oidc.signIn') {
+          return `Continue with ${params?.providerName ?? ''}`.trim()
+        }
+        if (key === 'auth.oauthOrContinue') {
+          return 'or continue'
+        }
+        return key
+      },
+    }),
+  }
+})
+
+type WeChatPublicSettings = PublicSettings & {
+  wechat_oauth_open_enabled?: boolean
+  wechat_oauth_mp_enabled?: boolean
+}
+
+function buildPublicSettings(overrides: Partial<WeChatPublicSettings> = {}): WeChatPublicSettings {
+  return {
+    registration_enabled: true,
+    email_verify_enabled: false,
+    force_email_on_third_party_signup: false,
+    registration_email_suffix_whitelist: [],
+    promo_code_enabled: true,
+    password_reset_enabled: false,
+    invitation_code_enabled: false,
+    turnstile_enabled: false,
+    turnstile_site_key: '',
+    site_name: 'Sub2API',
+    site_logo: '',
+    site_subtitle: '',
+    api_base_url: '/api/v1',
+    contact_info: '',
+    doc_url: '',
+    home_content: '',
+    hide_ccs_import_button: false,
+    payment_enabled: false,
+    table_default_page_size: 20,
+    table_page_size_options: [10, 20, 50, 100],
+    custom_menu_items: [],
+    custom_endpoints: [],
+    linuxdo_oauth_enabled: false,
+    wechat_oauth_enabled: true,
+    oidc_oauth_enabled: false,
+    oidc_oauth_provider_name: 'OIDC',
+    backend_mode_enabled: false,
+    version: 'test',
+    balance_low_notify_enabled: false,
+    account_quota_notify_enabled: false,
+    balance_low_notify_threshold: 0,
+    ...overrides,
+  }
+}
+
+function seedPublicSettings(overrides: Partial<WeChatPublicSettings> = {}): void {
+  const appStore = useAppStore()
+  const settings = buildPublicSettings(overrides)
+  appStore.cachedPublicSettings = settings
+  appStore.publicSettingsLoaded = true
+}
 
 describe('WechatOAuthSection', () => {
   beforeEach(() => {
+    pinia = createPinia()
+    setActivePinia(pinia)
     routeState.query = { redirect: '/billing?plan=pro' }
     locationState.current = { href: 'http://localhost/login' }
     Object.defineProperty(window, 'location', {
@@ -46,8 +107,16 @@ describe('WechatOAuthSection', () => {
     vi.unstubAllGlobals()
   })
 
-  it('starts the open WeChat OAuth flow with the current redirect target', async () => {
-    const wrapper = mount(WechatOAuthSection)
+  it('starts the open WeChat OAuth flow with the current redirect target when open mode is configured', async () => {
+    seedPublicSettings({
+      wechat_oauth_open_enabled: true,
+      wechat_oauth_mp_enabled: false,
+    })
+    const wrapper = mount(WechatOAuthSection, {
+      global: {
+        plugins: [pinia],
+      },
+    })
 
     expect(wrapper.text()).toContain('WeChat')
 
@@ -58,12 +127,20 @@ describe('WechatOAuthSection', () => {
     )
   })
 
-  it('uses mp mode inside the WeChat browser', async () => {
+  it('uses mp mode inside the WeChat browser when mp mode is configured', async () => {
     Object.defineProperty(window.navigator, 'userAgent', {
       configurable: true,
       value: 'Mozilla/5.0 MicroMessenger',
     })
-    const wrapper = mount(WechatOAuthSection)
+    seedPublicSettings({
+      wechat_oauth_open_enabled: false,
+      wechat_oauth_mp_enabled: true,
+    })
+    const wrapper = mount(WechatOAuthSection, {
+      global: {
+        plugins: [pinia],
+      },
+    })
 
     await wrapper.get('button').trigger('click')
 
@@ -71,4 +148,63 @@ describe('WechatOAuthSection', () => {
       '/api/v1/auth/oauth/wechat/start?mode=mp&redirect=%2Fbilling%3Fplan%3Dpro'
     )
   })
+
+  it('disables the button outside the WeChat browser when only mp mode is configured', async () => {
+    seedPublicSettings({
+      wechat_oauth_open_enabled: false,
+      wechat_oauth_mp_enabled: true,
+    })
+    const wrapper = mount(WechatOAuthSection, {
+      global: {
+        plugins: [pinia],
+      },
+    })
+
+    expect(wrapper.get('button').attributes('disabled')).toBeDefined()
+    expect(wrapper.text()).toContain('Open this page inside WeChat to continue.')
+
+    await wrapper.get('button').trigger('click')
+
+    expect(locationState.current.href).toBe('http://localhost/login')
+  })
+
+  it('disables the button inside the WeChat browser when only open mode is configured', async () => {
+    Object.defineProperty(window.navigator, 'userAgent', {
+      configurable: true,
+      value: 'Mozilla/5.0 MicroMessenger',
+    })
+    seedPublicSettings({
+      wechat_oauth_open_enabled: true,
+      wechat_oauth_mp_enabled: false,
+    })
+    const wrapper = mount(WechatOAuthSection, {
+      global: {
+        plugins: [pinia],
+      },
+    })
+
+    expect(wrapper.get('button').attributes('disabled')).toBeDefined()
+    expect(wrapper.text()).toContain('This site only has WeChat website login configured. Open this page in your browser to continue.')
+
+    await wrapper.get('button').trigger('click')
+
+    expect(locationState.current.href).toBe('http://localhost/login')
+  })
+
+  it('uses the legacy overall enabled flag when per-mode settings are not present', async () => {
+    seedPublicSettings({
+      wechat_oauth_enabled: true,
+    })
+    const wrapper = mount(WechatOAuthSection, {
+      global: {
+        plugins: [pinia],
+      },
+    })
+
+    await wrapper.get('button').trigger('click')
+
+    expect(locationState.current.href).toContain(
+      '/api/v1/auth/oauth/wechat/start?mode=open&redirect=%2Fbilling%3Fplan%3Dpro'
+    )
+  })
 })