diff --git a/CMakeLists.txt b/CMakeLists.txt
index e29a1c39d8..f3688766bb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -95,7 +95,7 @@ include(GNUInstallDirs)
 
 configure_file(${PROJECT_SOURCE_DIR}/config.h.in ${PROJECT_SOURCE_DIR}/src/butil/config.h @ONLY)
 
-set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
+list(APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake")
 
 find_package(GFLAGS REQUIRED)