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 model of the support structure was established under the restriction of the lowest natural frequency. The topology optimization design was carried out by using OptiStruct software. Then, the modal analysis and random vibration response analysis of the optimized support structure were made by using finite element analysis software MSC.Patran&Nastran. The natural frequency was 327 Hz, the maximum amplification rate of the RMS value of the installation point was 0.55. Finally, the support structure was tested with the random vibration test. The test results are in good agreement with the finite element analysis results, and the maximum error is 0.07. The support structure of star sensor meets the requirements of the performance index for micro satellite.