diff --git a/main.py b/main.py
index abe427f..806b4bb 100644
--- a/main.py
+++ b/main.py
@@ -827,6 +827,16 @@ class CameraWorker(QThread):
                             f"等待帧同步…RGB-D 差 {ts_diff}ms（{self._sync_wait_count}/10）")
                     continue
 
+                # 快速丢弃 SDK 内部缓冲中的旧帧，只保留最新帧以降低延迟
+                for _ in range(20):
+                    try:
+                        newer = pipeline.wait_for_frames(1)
+                        if newer is None:
+                            break
+                        frames = newer
+                    except Exception:
+                        break
+
                 # 预览
                 # HDR merge：用 merged 帧集替换深度帧
                 display_frames = frames
@@ -2002,7 +2012,7 @@ class MainWindow(QMainWindow):
         self._worker.set_splat(self.capture_splat_combo.currentData())
         if self.hdr_check.isChecked():
             self._worker.set_hdr(True)
-        self._worker.preview_ready.connect(self._on_preview_ready)
+        self._worker.preview_ready.connect(self._update_preview)
         self._worker.capture_done.connect(self._on_capture_done)
         self._worker.params_ready.connect(self._on_params_ready)
         self._worker.log_msg.connect(self._append_d2c_log)