In order to facilitate optical polishing of silicon carbide space telescope, in the present paper, silicon film, which has similar coefficient of thermal expansion with silicon carbide, was fabricated on SiC substrate by radio frequency magnetron sputtering. The effect of substrate temperature, radio frequency power, and substrate bias voltage was investigated by Raman scattering. The results indicate that at lower substrate temperature, the crystalline volume fraction of Si films increases with the increase in deposition temperature. Exceeding a certain temperature, the crystalline volume fraction decreases with further increasing deposition temperature; the increase in substrate bias voltage is bad for forming crystalline structure; the effect of radio power on microstructure of silicon film is comparatively complicated. As the rf power increases, the cluster size and crystallite volume fraction decrease, and both of them increase with further increasing the rf power. But when the rf power is too high, the crystallite volume fraction of the silicon film will decrease slightly.