diff --git a/src/tg_bot.py b/src/tg_bot.py
index ca056e2..f98fee9 100644
--- a/src/tg_bot.py
+++ b/src/tg_bot.py
@@ -365,7 +365,13 @@ def _handle_callback(bot_token: str, cfg: Config, cb: dict):
 
     if action == CALLBACK_VIEW_ORIG and ctx:
         can_reply = ctx.get("can_reply", True)
-        text = f"*📄 原文 \\- {_escape(ctx['subject'])}*\n\n{_escape(ctx.get('plain_text', ctx['original_body']))}"
+        subject = ctx.get("subject", "邮件")
+        body = ctx.get("plain_text", ctx["original_body"])
+        if len(body) > 3500:
+            body = body[:3500] + "\n\n... (内容过长已截断)"
+        # 用代码块包裹原文，避免 MarkdownV2 解析特殊字符
+        escaped_body = body.replace("\\", "\\\\").replace("`", "\\`")
+        text = f"*📄 原文 \\- {_escape(subject)}*\n\n`{escaped_body}`"
         _tg_req(bot_token, "editMessageText", {
             "chat_id": chat_id, "message_id": msg_id,
             "text": text, "parse_mode": "MarkdownV2",