The interface formation and band lineup of the C 6 0 /Si(111) are studied using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). It was found that there was no chemical reaction and diffusion between C 6 0 overlayer and Si(111) substrate. The results showed that the C 6 0 /Si(111) interface was abrupt. According to the data of the core-level rigid shift and the top of the valence band, we obtained that the valence band offset ΔE V of C 6 0 /Si(111) heterojunction was equal to 0.40eV.