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 950 °C. Nearly single-crystalline 3C-SiC film grew under the ratio of the flow rate of C3H8 to the flow rate of SiH4 (C/Si) of 2 - 2.5. From these results, it is suggested that C/Si shifts into higher with decreasing the substrate temperature. The crystallinity has been investigated by a 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.