In an effort to search for new inorganic fullerene-like structures, we designed a series of novel silicon-carbon cages, (SiC)n (n=6-36), based on the uniformly hybrid Si-C four-and six-membered-rings, and researched their geometrical and electronic structures, as well as their relative stabilities using the density function theory. Among these cages, the structures for n=12, 16, and 36 were found to been energetically more favorable. The calculated disproportionation energy and binding energy per SiC unit show that the (SiC) 12 cage is the most stable one among these designed structures. The present calculations not only indicate that silicon-carbon fullerenes are promised to be synthesized in future, but also provide a new way for stabilizing silicon cages by uniformly doping carbon atoms into silicon structures.