Using pure tungsten and titanium as targets, Ti-doped WOx films were deposited on the ITO glass by Reactive Magnetron Sputtering in order to improve the electrochromic properties of WOx films . The electrochromic performances and structure of the films were analyzed by XRD and transmittance spectrum of the films. The influence mechanism of Ti doping on the electrochromic performances and structure of WOx films were studied. As demonstrated in the experiment, the mixed film is still in the amorphous state, and tends to be stronger. The cyclic life span and the ability of color storage can be significantly improved as well as the response time were shorted due to Ti cloning.