diff --git a/build.sh b/build.sh
index 1a85b84..1d0fcb5 100755
--- a/build.sh
+++ b/build.sh
@@ -77,7 +77,11 @@ elif [ "$sys" == "kylin" ];then
 fi
 
 cd ../
-mkdir build
+if [ -f ./build/CMakeCache.txt ]; then
+    rm -rf ./build/*
+else
+    mkdir build
+fi
 cd build 
 cmake ../code_device
 make