diff --git a/services/kdocs_uploader.py b/services/kdocs_uploader.py
index 281c37c..67ed43a 100644
--- a/services/kdocs_uploader.py
+++ b/services/kdocs_uploader.py
@@ -7,6 +7,7 @@ import os
 import queue
 import threading
 import time
+from io import BytesIO
 from typing import Any, Dict, Optional
 
 import database
@@ -470,6 +471,8 @@ class KDocsUploader:
                     continue
                 width = box.get("width", 0)
                 height = box.get("height", 0)
+                if width < 160 or height < 160:
+                    continue
                 if vp_width and vp_height:
                     if width > vp_width * 0.92 and height > vp_height * 0.92:
                         continue
@@ -486,6 +489,27 @@ class KDocsUploader:
         except Exception:
             return None
 
+    def _is_valid_qr_image(self, data: Optional[bytes]) -> bool:
+        if not data or len(data) < 1024:
+            return False
+        try:
+            from PIL import Image, ImageStat
+
+            img = Image.open(BytesIO(data))
+            width, height = img.size
+            if width < 120 or height < 120:
+                return False
+            ratio = width / float(height or 1)
+            if ratio < 0.6 or ratio > 1.4:
+                return False
+            gray = img.convert("L")
+            stat = ImageStat.Stat(gray)
+            if stat.stddev[0] < 5:
+                return False
+            return True
+        except Exception:
+            return len(data) >= 2048
+
     def _save_login_state(self) -> None:
         try:
             storage_state = getattr(config, "KDOCS_LOGIN_STATE_FILE", "data/kdocs_login_state.json")
@@ -515,14 +539,18 @@ class KDocsUploader:
 
         self._ensure_login_dialog()
         qr_image = None
+        invalid_qr = None
         for _ in range(10):
             self._ensure_login_dialog()
-            qr_image = self._capture_qr_image()
-            if qr_image:
+            candidate = self._capture_qr_image()
+            if candidate and self._is_valid_qr_image(candidate):
+                qr_image = candidate
                 break
+            if candidate:
+                invalid_qr = candidate
             time.sleep(1)
         if not qr_image:
-            self._last_error = "二维码获取失败"
+            self._last_error = "二维码识别异常" if invalid_qr else "二维码获取失败"
             try:
                 pages = self._iter_pages()
                 page_urls = [getattr(p, "url", "") for p in pages]
@@ -538,6 +566,14 @@ class KDocsUploader:
                         continue
                 if saved:
                     logger.warning(f"[KDocs] 已保存调试截图: {saved}")
+                if invalid_qr:
+                    try:
+                        path = f"data/kdocs_invalid_qr_{ts}.png"
+                        with open(path, "wb") as handle:
+                            handle.write(invalid_qr)
+                        logger.warning(f"[KDocs] 已保存无效二维码截图: {path}")
+                    except Exception:
+                        pass
             except Exception:
                 pass
             return {"success": False, "error": self._last_error}