The effects of preparation conditions on WO3 films using RF reactive sputtering were investigated in order to prepare a high efficiency semiconductor electrode. The properties of the electrodes were measured in the solution of H2SO4. We found the optimum condition for the photocurrent in our system. The photocurrent is independent of O-2 concentration in the range of 20-50%. We suppose that a photocurrent Of WO3 depends on an orientation and a grain size. The result of XRD spectra corresponded well with SEM image. From the SEM images and the absorption spectra it was considered that the thicker the WO3 films were the rougher the surface became. (c) 2006 Elsevier B.V. All rights reserved.