diff --git a/packages/frontend/core/src/components/affine/auth/ai-login-required.tsx b/packages/frontend/core/src/components/affine/auth/ai-login-required.tsx
new file mode 100644
index 000000000000..7d4dd77ac219
--- /dev/null
+++ b/packages/frontend/core/src/components/affine/auth/ai-login-required.tsx
@@ -0,0 +1,41 @@
+import { useConfirmModal } from '@affine/component';
+import { authAtom } from '@affine/core/atoms';
+import { useAFFiNEI18N } from '@affine/i18n/hooks';
+import { atom, useAtom, useSetAtom } from 'jotai';
+import { useCallback, useEffect } from 'react';
+
+export const showAILoginRequiredAtom = atom(false);
+
+export const AiLoginRequiredModal = () => {
+  const t = useAFFiNEI18N();
+  const [open, setOpen] = useAtom(showAILoginRequiredAtom);
+  const setAuth = useSetAtom(authAtom);
+  const { openConfirmModal, closeConfirmModal } = useConfirmModal();
+
+  const openSignIn = useCallback(() => {
+    setAuth(prev => ({ ...prev, openModal: true }));
+  }, [setAuth]);
+
+  useEffect(() => {
+    if (open) {
+      openConfirmModal({
+        title: t['com.affine.ai.login-required.dialog-title'](),
+        description: t['com.affine.ai.login-required.dialog-content'](),
+        onConfirm: () => {
+          setOpen(false);
+          openSignIn();
+        },
+        confirmButtonOptions: {
+          children: t['com.affine.ai.login-required.dialog-confirm'](),
+          type: 'primary',
+        },
+        cancelText: t['com.affine.ai.login-required.dialog-cancel'](),
+        onOpenChange: setOpen,
+      });
+    } else {
+      closeConfirmModal();
+    }
+  }, [closeConfirmModal, open, openConfirmModal, openSignIn, setOpen, t]);
+
+  return null;
+};
diff --git a/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/copilot-client.ts b/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/copilot-client.ts
index 8239badde8e9..4435c5b9ab29 100644
--- a/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/copilot-client.ts
+++ b/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/copilot-client.ts
@@ -1,3 +1,4 @@
+import { showAILoginRequiredAtom } from '@affine/core/components/affine/auth/ai-login-required';
 import {
   createCopilotMessageMutation,
   createCopilotSessionMutation,
@@ -14,6 +15,7 @@ import {
   PaymentRequiredError,
   UnauthorizedError,
 } from '@blocksuite/blocks';
+import { getCurrentStore } from '@toeverything/infra';
 
 type OptionsField<T extends GraphQLQuery> =
   RequestOptions<T>['variables'] extends { options: infer U } ? U : never;
@@ -29,6 +31,7 @@ const fetcher = async <Query extends GraphQLQuery>(
 
     switch (code) {
       case 401:
+        getCurrentStore().set(showAILoginRequiredAtom, true);
         throw new UnauthorizedError();
       case 402:
         throw new PaymentRequiredError();
diff --git a/packages/frontend/core/src/providers/modal-provider.tsx b/packages/frontend/core/src/providers/modal-provider.tsx
index 47168ef91d26..0de5b078b1b8 100644
--- a/packages/frontend/core/src/providers/modal-provider.tsx
+++ b/packages/frontend/core/src/providers/modal-provider.tsx
@@ -88,6 +88,12 @@ const HistoryTipsModal = lazy(() =>
   }))
 );
 
+const AiLoginRequiredModal = lazy(() =>
+  import('../components/affine/auth/ai-login-required').then(module => ({
+    default: module.AiLoginRequiredModal,
+  }))
+);
+
 export const Setting = () => {
   const [{ open, workspaceMetadata, activeTab }, setOpenSettingModalAtom] =
     useAtom(openSettingModalAtom);
@@ -206,6 +212,7 @@ export function CurrentWorkspaceModals() {
       {currentWorkspace?.flavour === WorkspaceFlavour.AFFINE_CLOUD && (
         <CloudQuotaModal />
       )}
+      <AiLoginRequiredModal />
     </>
   );
 }
diff --git a/packages/frontend/i18n/src/resources/en.json b/packages/frontend/i18n/src/resources/en.json
index f5235db815a3..05f8cc647d0d 100644
--- a/packages/frontend/i18n/src/resources/en.json
+++ b/packages/frontend/i18n/src/resources/en.json
@@ -1304,5 +1304,9 @@
   "com.affine.ai-onboarding.local.action-dismiss": "Dismiss",
   "com.affine.ai-onboarding.local.action-learn-more": "Learn More",
   "com.affine.ai-onboarding.edgeless.title": "Meet AFFiNE AI",
-  "com.affine.ai-onboarding.edgeless.message": "Lets you think bigger, create faster, work smarter and save time for every project."
+  "com.affine.ai-onboarding.edgeless.message": "Lets you think bigger, create faster, work smarter and save time for every project.",
+  "com.affine.ai.login-required.dialog-title": "Sign in to Continue",
+  "com.affine.ai.login-required.dialog-content": "To use AFFiNE AI, please sign in to your AFFiNE Cloud account.",
+  "com.affine.ai.login-required.dialog-confirm": "Sign in",
+  "com.affine.ai.login-required.dialog-cancel": "Cancel"
 }