diff --git a/tests/test_transfer.py b/tests/test_transfer.py
index c056c7a..637b734 100644
--- a/tests/test_transfer.py
+++ b/tests/test_transfer.py
@@ -270,3 +270,15 @@ def test_speed_stats_empty():
 def test_speed_stats_single():
     cur, peak, avg = transfer.speed_stats([8 * 1024 * 1024])
     assert (cur, peak, avg) == (8 * 1024 * 1024, 8 * 1024 * 1024, 8 * 1024 * 1024)
+
+# ---------- 目录大小轮询 (rsync 输出缓冲替代方案) ----------
+
+def test_dir_size_returns_bytes(tmp_path):
+    """du 目录返回字节数"""
+    (tmp_path / "a.bin").write_bytes(b"x" * 1000)
+    (tmp_path / "sub").mkdir()
+    (tmp_path / "sub" / "b.bin").write_bytes(b"y" * 500)
+    assert transfer.dir_size(str(tmp_path)) == 1500
+
+def test_dir_size_missing_returns_zero():
+    assert transfer.dir_size("/nonexistent/path/xyz") == 0
diff --git a/transfer.py b/transfer.py
index 572a502..79d764c 100644
--- a/transfer.py
+++ b/transfer.py
@@ -55,6 +55,18 @@ def human_speed(bps: float) -> str:
     return f"{human_size(bps)}/s"
 
 
+def dir_size(path: str) -> int:
+    """du 目录字节数 (轮询进度用, 绕过 rsync 输出缓冲)"""
+    if not os.path.isdir(path):
+        return 0
+    try:
+        proc = subprocess.run(["du", "-sb", path],
+                              capture_output=True, text=True, timeout=30)
+        return int(proc.stdout.split()[0])
+    except (ValueError, OSError, subprocess.TimeoutExpired):
+        return 0
+
+
 def speed_stats(history) -> tuple[float, float, float]:
     """速度统计: (当前, 峰值, 平均) 字节/秒"""
     if not history:
@@ -547,40 +559,41 @@ class TaskRunner:
 
     # -- 执行
     def run(self) -> int:
-        """同步执行传输, 返回退出码"""
+        """同步执行传输, 返回退出码 (进度由目录轮询驱动, 绕过后端输出缓冲)"""
         cmd = self.build_command()
         self.lm.open_session(f"{self.cfg.backend}_{os.path.basename(self.cfg.source.rstrip('/'))}")
         self.lm.write(f"cmd: {' '.join(cmd)}")
         self.lm.write(f"mode: {self.cfg.backend} bwlimit={self.cfg.bwlimit or 'off'} "
                       f"resume={self.cfg.resume} checksum={self.cfg.checksum}")
+        # 源总大小 (进度分母)
+        self.total_bytes = dir_size(self.cfg.source.rstrip("/"))
+        self.lm.write(f"source size: {human_size(self.total_bytes)}")
+        # stdout 丢弃 (进度帧缓冲不可靠), stderr 单独读错误
         self.proc = subprocess.Popen(
-            cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
-            text=True, bufsize=0,
+            cmd, stdout=subprocess.DEVNULL, stderr=subprocess.PIPE,
+            text=True, bufsize=1,
         )
-        # rsync progress2 / rclone --progress 用 \r 刷新帧(不换行),
-        # 故按 \r 与 \n 均作分隔符分帧解析, 避免进度只取到末帧
-        assert self.proc.stdout is not None
-        buf = ""
-        while True:
-            chunk = self.proc.stdout.read(8192)
-            if not chunk:
+        # 轮询线程: 每秒统计目标目录大小驱动进度
+        self._stop.clear()
+        poll = threading.Thread(target=self._poll_loop, daemon=True)
+        poll.start()
+        assert self.proc.stderr is not None
+        for line in self.proc.stderr:
+            if self._stop.is_set():
                 break
-            buf += chunk
-            while True:
-                m = re.search(r"[\r\n]", buf)
-                if not m:
-                    break
-                seg, buf = buf[: m.start()], buf[m.start() + 1:]
-                if self._stop.is_set():
-                    self.proc.kill()
-                    break
-                self._dispatch(seg.rstrip())
-        if buf.strip() and not self._stop.is_set():
-            self._dispatch(buf.rstrip())
-        if self._stop.is_set():
-            self.proc.kill()
+            line = line.rstrip()
+            if line:
+                self._error(line)
         rc = self.proc.wait()
-        self.lm.write(f"exit code: {rc} (进度帧 {self.stats_frames} 次)")
+        self._stop.set()
+        poll.join(timeout=3)
+        # 最终统计
+        final = dir_size(self.cfg.dest.rstrip("/"))
+        self.stats.bytes_done = final
+        if self.total_bytes:
+            self.stats.pct = min(100.0, final / self.total_bytes * 100)
+        self.lm.write(f"exit code: {rc} (帧 {self.stats_frames} 次, "
+                      f"目标 {human_size(final)}/{human_size(self.total_bytes)})")
         removed = self.lm.prune()
         if removed:
             self.lm.write(f"pruned old logs: {len(removed)}")
@@ -588,6 +601,30 @@ class TaskRunner:
             self.on_done(rc)
         return rc
 
+    def _poll_loop(self) -> None:
+        """每秒轮询目标目录大小, 更新进度 (独立线程)"""
+        dst = self.cfg.dest.rstrip("/")
+        last = dir_size(dst)
+        last_t = time.time()
+        poll = 0
+        while not self._stop.is_set():
+            time.sleep(1)
+            done = dir_size(dst)
+            now = time.time()
+            speed = (done - last) / max(0.1, now - last_t)
+            self.stats.bytes_done = done
+            self.stats.bytes_total = self.total_bytes
+            self.stats.speed_bps = max(0, speed)
+            if self.total_bytes:
+                self.stats.pct = min(100.0, done / self.total_bytes * 100)
+            last, last_t = done, now
+            self._emit_stats()
+            poll += 1
+            # 每 5 秒一条进度快照到日志栏
+            if self.on_log and poll % 5 == 0:
+                self.on_log(f"已传 {human_size(done)} / {human_size(self.total_bytes)} "
+                            f"({self.stats.pct:.0f}%) {human_speed(self.stats.speed_bps)}")
+
     def stop(self) -> None:
         self._stop.set()
         if self.proc and self.proc.poll() is None: