diff --git a/cpp/.gitignore b/cpp/.gitignore
index 718081be75596480141ebfd5c3f6df94b90acf8d..71ee3f37704ffb7de21b320698d6334d2d75faa4 100644
--- a/cpp/.gitignore
+++ b/cpp/.gitignore
@@ -2,7 +2,6 @@ milvus/
 conf/server_config.yaml
 conf/log_config.conf
 version.h
-megasearch/
 lcov_out/
 base.info
 output.info
diff --git a/cpp/build.sh b/cpp/build.sh
index 1baad7d1c6c689c2c6f21b7190f1354d1046b177..104ecc89d3d8c85f352d550de3048cf739a775b3 100755
--- a/cpp/build.sh
+++ b/cpp/build.sh
@@ -11,8 +11,9 @@ PROFILING="OFF"
 BUILD_FAISS_WITH_MKL="OFF"
 USE_JFROG_CACHE="OFF"
 KNOWHERE_OPTS=""
+KNOWHERE_BUILD_DIR="`pwd`/thirdparty/knowhere/knowhere"
 
-while getopts "p:d:t:uhlrcgmj" arg
+while getopts "p:d:t:k:uhlrcgmj" arg
 do
         case $arg in
              t)
@@ -44,6 +45,9 @@ do
              g)
                 PROFILING="ON"
                 ;;
+             k)
+                KNOWHERE_BUILD_DIR=$OPTARG
+                ;;
              m)
                 BUILD_FAISS_WITH_MKL="ON"
                 ;;
@@ -63,11 +67,12 @@ parameter:
 -r: remove previous build directory(default: OFF)
 -c: code coverage(default: OFF)
 -g: profiling(default: OFF)
+-k: specify knowhere header/binary path
 -m: build faiss with MKL(default: OFF)
 -j: use jfrog cache build directory
 
 usage:
-./build.sh -t \${BUILD_TYPE} [-u] [-h] [-g] [-r] [-c] [-m] [-j]
+./build.sh -t \${BUILD_TYPE} [-u] [-h] [-g] [-r] [-c] [-k] [-m] [-j]
                 "
                 exit 0
                 ;;
@@ -83,12 +88,6 @@ if [[ ! -d cmake_build ]]; then
 	MAKE_CLEAN="ON"
 fi
 
-# Knowhere build output path
-KNOWHERE_BUILD_DIR="`pwd`/thirdparty/knowhere/knowhere"
-pushd `pwd`/thirdparty/knowhere
-./build.sh -t ${BUILD_TYPE} -p ${KNOWHERE_BUILD_DIR} ${KNOWHERE_OPTS}
-popd
-
 cd cmake_build
 
 CUDA_COMPILER=/usr/local/cuda/bin/nvcc