Abstract: SiC ceramic materials are well-known for its excellent thermo-mechanical properties, and its advantages compared with hollow glass microspheres make it one of the candidates for ICF target application. SiC ceramic microspheres were fabricated by drop-tower technique by using polycarbosilane (PCS) as raw material. The reaction mechanism of precursor pyrolysis and the effects of irradiation and carbonization on the SiC hollow microspheres were investigated. The results show that the ceramic yield at 850 ℃ is 65%, and the temperature at which the PCS begins to decompose is from 400 ℃ to 800 ℃. Bridge structure of SiCSi or SiOSi was formed in the irradiated products, and in the process of pyrolysis, SiH bonds, CH bonds and SiCH3 groups were partly broken down, the structure of SiCSi was formed. In addition, the influence of irradiation is to maintain the spheres frame during carbonization at high temperature and to increase the surface finish quality and evenness of hollow SiC ceramic microspheres.