In order to further improve the spatial resolution of the super-resolution satellite load optical system, it is necessary to suppress the stray light of the system to obtain accurate original images. By ray tracing, the stray light is analyzed, and the source of stray light is confirmed. Through the quantitative analysis and structural finite element analysis by Traccpro, the size of the hood and the position of the block were optimized, the point sources transmittance of the external point of the optical system is 10-3. The stray light suppression scheme is effective. The stray light suppression measures proposed in this paper provide theoretical support for the engineering application of Cassegrain optical system.