Indium tin oxide films(In2O3-SnO2)were deposited onto glass at different oxygen flows by R.F. magnetron sputtering method. Transmittance in visible light and an energy band gap were measured by ultraviolet spectrophotometer . square resistance was measured by four-point probe. The thickness and complex refractive index of films were measured by spectroscopic ellipsomtry. The component of the ITO films was studied by XPS. The study indicates that the deposited ratio and refractive indexes of films are related to the O2 flow rate, The transmittance in visible light is beyond 80% (including glass substrate) with the film thickness 60nm and 9sccm oxygen flux. The transmittance and square resistance can be improved by hot treatment. XPS investigation shows that the photoelectricity properties can be deteriorated by the sub-oxides, which can be reduced by oxygen flux.