A practical method is proposed for aberration correction in the catadioptric imaging system design. Based on the analytical relationship between the object distance and the image distance of the aspherical mirror imaging system in the meridional plane, the catadioptric imaging system aberration correction becomes a refractive lens optimization problem that is much simpler, thus there is no need of a complex surface figure to insure the optimization convergence. With the proposed method, it is convenient for the designer to keep the aberrations at a low level throughout the process and to focus on distortion correction or search for robust initial configuration. The design process of a catadioptric ultrashort distance projector is presented to illustrate the proposed method more clearly. The real performance of the ultrashort distance projector is also presented.