Abstract: Polycrystalline ZnO films were deposited on glass substrates by radio frequency (RF) magnetron sputtering technique. The as-deposited films were annealed at various temperatures (350～600℃) in air and at 600℃ in N2. The influence of sputtering parameters such as sputtering power, O2 partial pressure, substrate temperature and annealing on the crystallization of the ZnO films was investigated by X-ray diffraction (XRD). The results show that the crystallization of the film has been promoted by desirable substrate temperature or annealing.