diff --git a/deploy/cpp_infer/CMakeLists.txt b/deploy/cpp_infer/CMakeLists.txt
index 4f2dc88a8f1a9d185b7274a1a723c0e670bd1bf1..5e009f98e46d820c0f652af334f9caf30a9adaa3 100644
--- a/deploy/cpp_infer/CMakeLists.txt
+++ b/deploy/cpp_infer/CMakeLists.txt
@@ -71,7 +71,7 @@ else()
     if(WITH_MKL)
         set(FLAG_OPENMP "-fopenmp")
     endif()
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -o3 ${FLAG_OPENMP} -std=c++11")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -O3 ${FLAG_OPENMP} -std=c++11")
     set(CMAKE_STATIC_LIBRARY_PREFIX "")
     message("cmake cxx flags" ${CMAKE_CXX_FLAGS})
 endif()