ZnO thin films were grown on (0001) LiNbO 3 substrates by the MOCVD technique. The substrate temperatures during growth were changed from 400 to 600°C. The X-ray diffraction (XRD) pattern of the ZnO film showed a strong [002] reflection peak, and the peak intensity was dependent on substrate temperature. The ZnO columnar grains were highly oriented along the (002) direction when the film processing temperature was 600°C. The optical transmission and PL results also indicated that highest crystalline quality of the ZnO films could be obtained at elevated temperatures.