diff --git a/src/renderer/src/services/ModelMessageService.ts b/src/renderer/src/services/ModelMessageService.ts
index 4e9c1d5729..b48543ea19 100644
--- a/src/renderer/src/services/ModelMessageService.ts
+++ b/src/renderer/src/services/ModelMessageService.ts
@@ -57,7 +57,7 @@ export function processPostsuffixQwen3Model(
     } else {
       // 思考模式未启用，添加 postsuffix
       if (!content.endsWith(postsuffix)) {
-        return content + postsuffix
+        return content + ' ' + postsuffix
       }
     }
   } else if (Array.isArray(content)) {