In order to demonstrate the formation of 3C-SiC film on Si (111) at low substrate temperature, the effects of C3H8 on the crystallinity of the films on Si (111) have been investigated by changing the flow rate of C3H8 at the substrate temperature of 850 °C. Oriented polycrystalline 3C-SiC film grew under the C/Si of 3 – 5 with a-C. It is suggested that etching effects of growing surface by hydrogen radicals generated from C3H8 decomposition is lowered by lowering the substrate temperature. The crystallinity has been investigated by reflection electron diffraction (RED) and a X-ray diffraction (XRD). The thickness and the surface roughness of the films were investigated by an ellipsometric measurement.