ZnO thin-film transistors(TFTs) prepared by magnetron sputtering method are investigated.The thermal growth SiO2 treated with NH3 is the device′s insulator layer,and the appropriate-thickness ZnO sputtered with fine Ar-O2 ratio is the device′s active layer.The results suggest that the device carrier mobility where SiO2 is treated with NH3 is at least one order of magnitude higher than that of the thermal growth SiO2 device.The optimal Ar-O2 ratio is 25∶1.The ZnO film thickness has great influence on the ZnO-TFT device performance.Four film thicknesses are selected,and the results indicate that 25 nm-thick ZnO films have the maximum mobility.