Motivated by the recent synthesis of silica-coated silicon nanotubes, we here present the structural models of their counterparts, silica-coated silicon fullerenes, which can be considered as arising from a structurally stable building block, Si3O2. By performing density functional theory calculations we show that the silica-coated silicon fullerenes possess high energetic and thermal stabilities and point group symmetries as well as large energy gaps. The present results indicate that coating silica on silicon clusters would be a new way for stabilizing silicon fullerenes, which is expected to find potential allocations in nanotechnology.