diff --git a/Protocol/HDSDK.cpp b/Protocol/HDSDK.cpp
index eebbeca..b8296f9 100644
--- a/Protocol/HDSDK.cpp
+++ b/Protocol/HDSDK.cpp
@@ -636,8 +636,8 @@ bool HDSDKPrivate::ParseSDKCmdAnswer(std::string &&data)
 
     sdkBuff_.append(data);
     if (total <= sdkBuff_.size()) {
-        std::string buff(sdkBuff_.substr(0, total));
-        sdkBuff_ = sdkBuff_.substr(total);
+        std::string buff(std::move(sdkBuff_));
+        sdkBuff_.clear();
         ReadXml(buff, 0);
     }