Development of advanced material and structure needs to combine advanced design method with progressive manufacturing technique. Topology optimization is not based on a priori assumptions of material distribution, resulting in providing innovative structures for engineers. Additive manufacturing involves the progressive addition of material to generate component geometry, which has strong ability to fabricate complex structure. The combination of topology optimization method and additive manufacturing technology, Topology optimization design of star tracker bracket of small satellite, then redefined the model of star tracker bracket, realized by additive manufacturing technology. The results show that the weight of star tracker was reduced significantly, and high strength and rigidity are guaranteed.