diff --git a/face_rec.py b/face_rec.py
index 7dbfbfa..4e654b6 100644
--- a/face_rec.py
+++ b/face_rec.py
@@ -692,9 +692,17 @@ class FaceRecognitionSystem:
             # 获取二维码图片尺寸
             qr_height, qr_width = qr_image.shape[:2]
 
-            # 使用屏幕缓存尺寸，如果获取失败则使用图片尺寸
-            canvas_width = self.screen_width if self.screen_width > 0 else qr_width
-            canvas_height = self.screen_height if self.screen_height > 0 else qr_height
+            # 使用屏幕尺寸，按比例缩放图片
+            canvas_width = self.screen_width
+            canvas_height = self.screen_height
+
+            # 等比例缩放：保持图片宽高比
+            scale = min(canvas_width / qr_width, canvas_height / qr_height)
+            scaled_width = int(qr_width * scale)
+            scaled_height = int(qr_height * scale)
+
+            # 缩放二维码图片
+            qr_image_scaled = cv2.resize(qr_image, (scaled_width, scaled_height), interpolation=cv2.INTER_LINEAR)
 
             # 创建二维码窗口
             cv2.namedWindow(self.qrcode_window_name, cv2.WINDOW_NORMAL | cv2.WINDOW_GUI_NORMAL)
@@ -702,24 +710,19 @@ class FaceRecognitionSystem:
             x_pos = 0
             y_pos = 0
 
-            rendered = self._build_qrcode_instruction_canvas(qr_image, (canvas_width, canvas_height))
+            rendered = self._build_qrcode_instruction_canvas(qr_image_scaled, (canvas_width, canvas_height))
             if rendered is None:
                 # 回退到原二维码展示
-                scale_width = canvas_width / qr_width
-                scale_height = canvas_height / qr_height
-                scale = min(scale_width, scale_height)
-                new_width = int(qr_width * scale)
-                new_height = int(qr_height * scale)
-                resized_qr = cv2.resize(qr_image, (new_width, new_height), interpolation=cv2.INTER_LINEAR)
+                resized_qr = qr_image_scaled
                 
                 # 创建背景画布
                 rendered = np.zeros((canvas_height, canvas_width, 3), dtype=np.uint8)
                 
                 # 计算居中位置
-                x_offset = (canvas_width - new_width) // 2
-                y_offset = (canvas_height - new_height) // 2
+                x_offset = (canvas_width - scaled_width) // 2
+                y_offset = (canvas_height - scaled_height) // 2
                 
-                rendered[y_offset:y_offset+new_height, x_offset:x_offset+new_width] = resized_qr
+                rendered[y_offset:y_offset+scaled_height, x_offset:x_offset+scaled_width] = resized_qr
 
             cv2.resizeWindow(self.qrcode_window_name, canvas_width, canvas_height)
             cv2.moveWindow(self.qrcode_window_name, x_pos, y_pos)