Functionalized graphene (FG) was prepared in one step by treating graphene oxide (GO) successively with hexadecyltrimethoxysilane and triethylamine. The FG sheets were subsequently assembled into a thin film by vacuum extraction filtering. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, X-ray diffraction, and Raman spectroscopy were employed to confirm the reduction and silane functionalization of GO to be simultaneously completed during the treatment. The presence of the long hexadecyl chain made the FG hydrophobic. The graphene film showed a high surface roughness, which consisted of many randomly stacked flakes, exhibiting a contact angle of up to 128.1A degrees.