ZnO thin films were deposited using a RF-sputtering technique on several kinds of LiNbO3 substrates having the surfaces prepared by cutting at specified crystalline orientations. The substrate temperatures during deposition were changed from 300 to 703 K in various oxygen-argon atmosphere. From X-ray diffraction (XRD) pattern, a strong ZnO [002] reflection peak was obtained for the film on z-cut LiNbO3 substrate. The peak intensity was dependent on gas flow rate of oxygen to argon, substrate temperature and anneal temperature. When the film was deposited on z-cut LiNbO3 substrate at 603 K in Ar (80%) and O-2 (20%), gas, it showed the crystalline growth highly oriented at (0 0 2) direction.