diff --git a/src/components/admin/AiAssistant.tsx b/src/components/admin/AiAssistant.tsx
index a140f85..e63d073 100644
--- a/src/components/admin/AiAssistant.tsx
+++ b/src/components/admin/AiAssistant.tsx
@@ -241,7 +241,7 @@ export default function AiAssistant({
       {hasSelection && (
         <div className="rounded-lg bg-primary/5 border border-primary/20 px-3 py-2">
           <p className="font-sans text-xs text-primary/70">
-            📌 已选中 <span className="font-medium">{selectedText.length}</span> 字，AI 将只处理选中内容
+            📌 已选中 <span className="font-medium">{selectedText?.length}</span> 字，AI 将只处理选中内容
           </p>
         </div>
       )}