The surface contribution analysis method is to find the wavefront map at the local intermediate entrance and exit pupil reference spheres for each optical surface. Direct pictures of each surface aberration contribution are then given by fitting the wavefront errors with Fringe Zernike polynomials which can help optical designers to find the origins of the main aberrations at the final focal plane and make them choose the effective variables for optimization consciously, which is very helpful for designing the freeform optical system with hundrands of variables. This paper discusses the surface contribution analysis method. A Matlab routine is written to communicate with Code V and to give direct pictures of aberration contribution for each surface. A compact freeform optical system is designed to validate the surface contribution analysis design method which is proved to have good convergence and very directive for optical designers.