Vanadium oxide films were deposited at different substrate temperatures up to 400 degrees C by DC magnetron sputtering, and through the method of the X-ray diffraction, electron scanning microscopy, infrared and Raman spectra, the present paper studies the structure properties of those films, and through the method of spectrum measuring and fitting, this paper studies the optical properties of the films. At low temperature of preparation the optical films have high optical transmittance. The films prepared at low substrate temperature (lower than 200 degrees C) have amorphous structure and some films prepared at high substrate temperatures (higher than 200 degrees C) have polycrystalline structure. The films' optical parameters were achieved by using classic model to fit the characteristic of transmittance.