The ZnS thin film was grown on Si substrate by radio frequency magnetron sputtering (RFSP).The structure and phase transition of the film were evaluated with X ray diffraction (XRD) technique.The results show some characterization of micro structure and phase transition of ZnS thin film prepared by RFSP.All of these can be used to gain an insight into the mechanism of TFEL and to find a new EL material with high brightness.