The higher intensity of ZnS:Li 2O thin film electroluminesence is reported.The blue emitting material of ZnS:Li 2O was sintered by us.we prepared ZnS:Li 2O devices with sandwich structure through EB evaporation.Through absorption spectra,EL spectra,relations between applied voltage and luminescence intensity,the thin film luminescence characters of ZnS:Li 2O is researched.We considered that the mechanism of ZnS:Li 2O thin film electroluminesence is due to interstitial zinc and oxygen that replaced the place of sulfer and oxygen can restrain the non radiant energy transportation through sulfur vacancy thus can improve the luminescence intensity.