According to the special requirements of star sensor for micro satellite, combined with special working performance and environment of star sensor, multi-objective optimization design was carried out on the support structure of star sensor by using topological method, and finite element analysis and test were also done. First, the basic theory of modal analysis and random vibration response were introduced in this paper. The expression formula of multi-objective topology optimization was derived. Second, the goal of optimization contains volume minimization of the support structure, and RMS value minimization of 4 installation point in the support structure where star sensor was installed. The topology optimization