diff --git a/build_iflow.sh b/build_iflow.sh
index 2f27f255713732857ef63bee85039f0d64f41f41..0a2abab9d3cfc72c6c4205e48b8b9b15adda5d71 100755
--- a/build_iflow.sh
+++ b/build_iflow.sh
@@ -39,26 +39,25 @@ export IFLOW_MIRROR_URL
 source $IFLOW_SHELL_DIR/common.sh
 
 # essential package
-RUN sudo apt install build-essential clang libreadline-dev bison flex libffi-dev cmake libboost-all-dev swig klayout libeigen3-dev libspdlog-dev -y
-
+RUN_ROOT apt install wget build-essential clang libreadline-dev bison flex libffi-dev cmake libboost-all-dev swig klayout libeigen3-dev libspdlog-dev -y
 # tcl
-RUN sudo apt install tcl-dev -y
-RUN sudo cp -f /usr/include/tcl8.6/*.h /usr/include/
-RUN sudo ln -s -f /usr/lib/x86_64-linux-gnu/libtcl8.6.so /usr/lib/x86_64-linux-gnu/libtcl8.5.so
+RUN_ROOT apt install tcl-dev -y
+RUN_ROOT cp -f /usr/include/tcl8.6/*.h /usr/include/
+RUN_ROOT ln -s -f /usr/lib/x86_64-linux-gnu/libtcl8.6.so /usr/lib/x86_64-linux-gnu/libtcl8.5.so
 
 # lemon
 CHECK_DIR /usr/local/include/lemon ||\
 {
-    RUN wget http://lemon.cs.elte.hu/pub/sources/lemon-1.3.1.tar.gz
-    RUN tar zxvf lemon-1.3.1.tar.gz
-    RUN cd lemon-1.3.1
-    RUN mkdir build 
-    RUN cd build 
-    RUN cmake .. 
-    RUN make -j$IFLOW_BUILD_THREAD_NUM 
-    RUN sudo make install
-    RUN cd ../../
-    RUN rm -rf lemon-1.3.1 lemon-1.3.1.tar.gz
+        RUN wget http://lemon.cs.elte.hu/pub/sources/lemon-1.3.1.tar.gz
+        RUN tar zxvf lemon-1.3.1.tar.gz
+        RUN cd lemon-1.3.1
+        CHECK_DIR build || RUN mkdir build
+        RUN cd build
+        RUN cmake ..
+        RUN make -j$IFLOW_BUILD_THREAD_NUM
+        RUN_ROOT make install
+        RUN cd ../../
+        RUN rm -rf lemon-1.3.1 lemon-1.3.1.tar.gz
 }
 
 # update iFlow
@@ -69,4 +68,4 @@ RUN git pull origin master
 RUN $IFLOW_SHELL_DIR/install_tools.sh
 
 # link iEDA lib
-echo 'export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:'$IFLOW_TOOLS_DIR'/iEDA_0.1/lib' >> ~/.bashrc
+echo 'export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:'$IFLOW_TOOLS_DIR'/iEDA_0.1/lib' >> ~/.bashrc
\ No newline at end of file
diff --git a/scripts/shell/common.sh b/scripts/shell/common.sh
index a63cf1d40f02aa51378d6257fd4a7f178275cf8d..2a86e13d3edab8a64ed4f9528953d9f700ddf5af 100755
--- a/scripts/shell/common.sh
+++ b/scripts/shell/common.sh
@@ -31,4 +31,13 @@ function RUN()
             echo "[iFlow Warning] Exec '$*' failed, retry..." && sleep 1
         fi
     done
+}
+
+function RUN_ROOT()
+{
+    if [ `whoami` = "root" ]; then
+        RUN $*
+    else
+        RUN sudo $*
+    fi
 }
\ No newline at end of file