The reflection optics with large aperture is widely used in spatial remote instruments. The imaging quality of the optics is closely related to the mirror surface deformation which caused by the mirror's supporting structure. An interface program between the mechanical finite element analysis and the optic design software is presented. In this way,it can directly study the deterioration of the optics imaging quality which caused by the supporting structure. During the design of the optical system,this method can also be used in integrated analysis of optics,mechanics and thermodynamics.