diff --git a/src/serial_port.cpp b/src/serial_port.cpp
index 5d133d7..4f9a2fb 100644
--- a/src/serial_port.cpp
+++ b/src/serial_port.cpp
@@ -50,11 +50,11 @@ void SerialPort::stop()
     stop_flag_ = true;
     running_ = false;
 
-    if (reader_thread_.joinable()) reader_thread_.join();
-
-    if (reconnect_thread_.joinable()) reconnect_thread_.join();
-
+    // 先关闭 fd，打断 reader 的阻塞 read()
     close_port();
+
+    if (reader_thread_.joinable()) reader_thread_.join();
+    if (reconnect_thread_.joinable()) reconnect_thread_.join();
 }
 
 bool SerialPort::open_port()
@@ -138,6 +138,13 @@ void SerialPort::reader_loop()
     running_ = false;
 }
 
+static void interruptible_sleep(std::atomic<bool>& stop_flag, int seconds)
+{
+    using namespace std::chrono;
+    for (int i = 0; i < seconds * 10 && !stop_flag.load(std::memory_order_relaxed); ++i)
+        std::this_thread::sleep_for(100ms);
+}
+
 void SerialPort::reconnect_loop()
 {
     int current_interval = retry_interval_;
@@ -159,7 +166,7 @@ void SerialPort::reconnect_loop()
         {
             LOG_INFO("[" + id_ + "] Connect failed, retry in " + std::to_string(current_interval) + "s");
 
-            std::this_thread::sleep_for(std::chrono::seconds(current_interval));
+            interruptible_sleep(stop_flag_, current_interval);
             current_interval = std::min(current_interval * 2, max_interval);
         }
     }