Vanadium oxide (V2O5) thin films with various thicknesses have been prepared by using the radio frequency (R.F.) sputtering method from V2O5 (ceramic) or V (metal) target. The electrochemical properties of the films were characterized as a function of the thickness. The films with thickness of 500 nm, fabricated from V2O5 ceramic target showed proper discharge capacity and cycle performance. However, the electrochemical property for the film with thickness of over 500 nm could not be observed due to the low deposition rate from V2O5 ceramic target and instability of interface between the surface and the film. The discharge capacity and cyclic performance of vanadium oxide films deposited from V metal target degraded with increasing thickness of the films. Considering the electrochemical properties of the films and the requirement of current density for the application field of thin film battery, appropriate thickness of vanadium oxide film for thin film battery was less than 1000 nm in our work.