diff --git a/core/src/index/CMakeLists.txt b/core/src/index/CMakeLists.txt
index 9125f6ea2c5fc2bdedd57533eaeaab341d047561..bedd35a4a2e18ffa1ab59ade567494685543dcfa 100644
--- a/core/src/index/CMakeLists.txt
+++ b/core/src/index/CMakeLists.txt
@@ -86,6 +86,10 @@ include(DefineOptionsCore)
 include(BuildUtilsCore)
 include(ThirdPartyPackagesCore)
 
+if (CUSTOMIZATION)
+    add_definitions(-DCUSTOMIZATION)
+endif (CUSTOMIZATION)
+
 add_subdirectory(knowhere)
 
 if (BUILD_COVERAGE STREQUAL "ON")
diff --git a/core/unittest/CMakeLists.txt b/core/unittest/CMakeLists.txt
index ac4fae85bb8af8a037fe24a8b2db9c208527367a..b87a9a05f7e965eff5fb3db6004c1b42c53f270b 100644
--- a/core/unittest/CMakeLists.txt
+++ b/core/unittest/CMakeLists.txt
@@ -16,6 +16,9 @@
 # specific language governing permissions and limitations
 # under the License.
 #-------------------------------------------------------------------------------
+if (CUSTOMIZATION)
+    add_definitions(-DCUSTOMIZATION)
+endif (CUSTOMIZATION)
 
 include_directories("${CUDA_TOOLKIT_ROOT_DIR}/include")