Abstract.This paper presents a novel method that using low energy hydrogen ion beam at normal incidence to deal with indium tin oxide(ITO) thin films.The surface structure of ITO thin films are controlled by changing parameters of ion source(IS),such as ion energy,ion beam current,substrate temperature and processing time.In this paper,the ion energy is set at 300 eV, the ion beam current ranges from 60 mA to 100 mA,the substrates are heated to 120 and 150 , the processing time is from 5 min to 25 min.Setting the ion source parameter at 300 eV,120and 60 mA,with the growing of time,the nanoparticles(NPs) on the surface of ITO layer appears,and the diameter of nanoparticles is reduced as the treating time is beyond 15 min.In addition to,transforming the ion beam current from 80 mA to 100 mA,other parameters,such as maintaining the ion energy at 300 eV, substrate temperature at 150and conducting time at 15 min,it demonstrates that the nanoparticles size of ITO layer is more uniform and dense nanostructures at 100 mA ion beam current than at 80 mA ion beam current.It means that altering the ion beam current could affect the nanoparticles size distribution and,furthermore,control the surface nanostructure of ITO layer.