Abstract: By using a hydrothermal method,well-aligned SnO₂ nanowire arrays were prepared on ITO substrates,which were pretreated by a magnetron sputtering method(MST-substrates).The samples were characterized by X-ray diffraction(XRD),field-emission scanning electron microscopy(SEM),transmission electron microscopy(TEM) and high-resolution transmission electron microscopy(HRTEM).The effects of film-coated methods and annealing temperature on the morphology,size and orientation were studied.The results show that the pretreating methods for substrates have great influence on the morphology and size of the samples.The SnO₂ nanowire,nanorod,nanoparticle arrays grow on different substrates,which were pretreated with magnetron sputtering,spin-casting methods and unmodified respectively.It is also found that annealing temperature for the pretreated substrates with magnetron sputtering plays a main role in controlling the orientation of SnO₂ nanowire arrays.The orientation of SnO₂ nanowire arrays is improved by increasing the annealing temperature.