This paper is aiming at jointly optimizing the design and analysis of the optics and digital image processing for imaging systems. The influence of each aberration on the imaging sharpness is analyzed according to the Zernike polynomial model. A digital image processing algorithm is proposed for aberration correction, which is based on the variational bayesian framework and weighted bi-direction difference prior. Then the aberrations are divided into two categories: easy to digital correct and hard to digital correct, so an optics-digital processing co-design method can be established based aberration optional-correction. At last, a three-lens large aberration optical system is designed by the co-design method, its MTF value at the nyquist frequency is about 0.50; in contrast, a six-lens system is designed by traditional method, and its MTF value is about 0.53. These results show that the imaging quality of two system is similar, therefore, the proposed method would be capable of reducing the complexity of the optical system.