diff --git a/src/api/controllers/chat.ts b/src/api/controllers/chat.ts
index b0b0486..eba551f 100644
--- a/src/api/controllers/chat.ts
+++ b/src/api/controllers/chat.ts
@@ -487,21 +487,48 @@ function extractRefFileUrls(messages: any[]) {
  * @param messages 参考gpt系列消息格式，多轮对话请完整提供上下文
  */
 function messagesPrepare(messages: any[], refs: any[]) {
-  // 只保留最新消息以及不包含"type": "image_url"或"type": "file"的消息
-  let validMessages = messages.filter((message, index) => {
-    if (index === messages.length - 1) return true;
-    if (!Array.isArray(message.content)) return true;
-    // 不含"type": "image_url"或"type": "file"的消息保留
-    return !message.content.some(v => (typeof v === 'object' && ['file', 'image_url'].includes(v['type'])));
+  // 先剔除所有的 base64 数据
+  let validMessages = messages.map((message) => {
+    if (Array.isArray(message.content)) {
+      message.content = message.content.filter(v => {
+        if (typeof v === 'object' && ['file', 'image_url'].includes(v['type'])) {
+          // 如果内容是 base64 数据，就剔除
+          return !util.isBASE64Data(v['url']);
+        }
+        // 如果不是 base64 数据，就保留
+        return true;
+      });
+    }
+    return message;
   });
 
+  // 检查最新消息是否含有"type": "image_url"或"type": "file",如果有则注入消息
+  let latestMessage = validMessages[validMessages.length - 1];
+  let hasFileOrImage = Array.isArray(latestMessage.content)
+    && latestMessage.content.some(v => (typeof v === 'object' && ['file', 'image_url'].includes(v['type'])));
+  if (hasFileOrImage) {
+    let newFileMessage = {
+      "content": "关注用户最新发送文件和消息结尾",
+      "role": "system"
+    };
+    validMessages.splice(validMessages.length - 1, 0, newFileMessage);
+    logger.info("检查注入文件消息");
+  } else {
+    let newTextMessage = {
+      "content": "关注用户消息的结尾",
+      "role": "system"
+    };
+    validMessages.splice(validMessages.length - 1, 0, newTextMessage);
+    logger.info("检查注入文本消息");
+  }
+
   const content =
     validMessages.reduce((content, message) => {
       if (_.isArray(message.content)) {
         return (
           message.content.reduce((_content, v) => {
             if (!_.isObject(v) || v["type"] != "text") return _content;
-            return _content + (v["text"] || "");
+            return _content + ('user:' + v["text"] || "") + "\n";
           }, content) + "\n"
         );
       }