Recently, the car industry is confront with various demands such as light weight and safety for a crash accident. But to achieve a light weight and safe car, design optimization is indispensable due to the many constraints in the auto-body. The response, surface method is the statistical method which can be applied to the non-sensitivity base optimization. In this paper, this scheme is utilized to improve the crash performance of the front side member in auto-body with the response surface method and the commercial finite element program, LS-DYNA 3D. Total 27 design points are selected to construct the response surface. With these design points, the response surface about the absorbed energy and the mass are constructed and then are utilized to optimize the crash performance of the front side member. The crash performance and the deformation patterns are evaluated to confirm the crashworthness enhancement