diff --git a/src/device/DeviceManager.cpp b/src/device/DeviceManager.cpp
index 61fc47e..4953956 100644
--- a/src/device/DeviceManager.cpp
+++ b/src/device/DeviceManager.cpp
@@ -94,7 +94,7 @@ void DeviceManager::initDevice() {
             {
                 lastStatus = SCANNING;
                 previewing = true;
-                timerID = startTimer(500);
+//                timerID = startTimer(500);
                 TRIGGER_EVENT(GUIEvents::ResponsePreview, nullptr, nullptr);
                 TRIGGER_EVENT(GUIEvents::InvokeOperationEnd, nullptr, nullptr);
                 return;
@@ -103,31 +103,32 @@ void DeviceManager::initDevice() {
         QString msg(inf.status!=READY?"Can't start preview,Device is not ready!":"Start preview operation fail!");
         THROW_ERROR(msg);
     });
+
+    previewDataCaller = QThread::create([=](){
+        while (!endLoop)
+        {
+            QThread::msleep(500);
+            if (!previewing) continue;
+            const char * data = GetPreviewData();
+            QByteArray bytes =QByteArray::fromRawData(data,140*140);
+            if (!previewing) continue;
+            TRIGGER_EVENT(GUIEvents::ResponsePreviewData, nullptr, (QObject*)(&bytes));
+        }
+    });
+    previewDataCaller->start();
 }
 
 void DeviceManager::timerEvent(QTimerEvent *event) {
     if (event->timerId() !=deviceInfTimerID)
     {
         StatusInfo inf = GetStatus();
-        printf("Timer request status, status:%s\r\n",getStatusString(inf.status));
+//        printf("Timer request status, status:%s\r\n",getStatusString(inf.status));
         if (inf.status==SCANNING)
         {
             lastStatus = SCANNING;
             //normal scan
-            if(!previewing)
-            {
-                QVariant var(inf.progress);
-                TRIGGER_EVENT(GUIEvents::InvokeOperationProgress, nullptr, (QObject*)&var);
-            }
-                //preview scan
-            else{
-                const char * data = GetPreviewData();
-                if (!data) return;
-                QByteArray bytes =QByteArray::fromRawData(data,140*140);
-                TRIGGER_EVENT(GUIEvents::ResponsePreviewData, nullptr, (QObject*)(&bytes));
-//                delete [] data;
-            }
-
+            QVariant var(inf.progress);
+            TRIGGER_EVENT(GUIEvents::InvokeOperationProgress, nullptr, (QObject*)&var);
         } else{
             if (lastStatus == SCANNING && !errorOccured)
             {
diff --git a/src/device/DeviceManager.h b/src/device/DeviceManager.h
index 0ddd74e..6f82a45 100644
--- a/src/device/DeviceManager.h
+++ b/src/device/DeviceManager.h
@@ -6,6 +6,7 @@
 #define GUI_DEVICEMANAGER_H
 
 #include <QObject>
+#include <QThread>
 class DeviceManager:public QObject {
     Q_OBJECT
 
@@ -25,7 +26,9 @@ private:
     int deviceInfTimerID = -1;
     int lastStatus=-1;
     bool previewing = false;
+    bool endLoop = false;
     bool errorOccured = false;
+    QThread* previewDataCaller;
 };