In this paper we studied switchable mirrors for application to transparent flat panel displays. The typical structure of switchable mirror has configuration of MgNi/Pd/Ta2O5/HxWO(3)/ITO. In this study photocatalyst layer (TiO2 or Nb2O5) was used between Pd and Ta2O5 layers. These layers were prepared by RF magnetron sputtering method utilizing TiO2 and Nb2O5 targets under various conditions and their electrochromic properties were investigated by using FE-SEM, EDAX and Nano View system. The transmittances of the Nb2O5 and the TiO2 thin films, could be optimized in the switchable mirror as photocatalyst layer, where they were deposited under the power of 80 W and 70 W, respectively, by the RF magnetron sputter. The characteristics of Nb2O5 and TiO2 transmittance are the outstanding at 80 W, 70 W respectively.