A kind of method of structural optimization design using structural deformation to compensate for optical misalignment is presented, which aims at decreasing the affection of imaging by gravity. First, on the basis of the characteristics of the optical system of a space camera, the structural forms of the main frame of the camera and the flexible support structure of the mirrors are determined. Secondly, taking the relative stiffness shift, relative inclination and face shape error of the secondary mirror, tertiary mirror, folding mirror, focusing mirror and main mirror under gravity as the optimization objectives, and the stability tolerance requirement of the optical system for each mirror as the constraints, the optimal parameters of the truss of main frame, the bearing cylinder thickness and the flexible support structure are obtained. Finally, the finite element analysis is carried out on the mode and Surface deformation of the camera, and sinusoidal sweep test and system wave aberration test are carried out on the camera. The results show that the first-order frequency of the camera is 36.7 Hz, and the average wave aberration of each field of the camera is 0.0655λ and 0.0701λ (λ=632.8 nm) under the two states of loading and flipping 180 degrees, respectively. It can be inferred that the wave aberration of the system can meet the optical design requirements after the gravity effect of the camera is disappeared. The optimized design of the camera support structure can be used as a reference for the structural design of space cameras.