Ceria supported on various commercial TiO2 catalysts were prepared by wet-impregnation method. We confirmed that the correlation between physicochemical properties of TiO2 supports and SCR activities. Physicochemical properties of the various TiO2 were evaluated using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, X-ray photoelectron spectro- scopy (XPS), and pH analysis. Ce/Ti catalyst exhibited different SCR activities with respect to physicochemical properties of TiO2. An excellent activity was obtained as the surface area of TiO2 increased. In the case of CeOx surface density, the excellent activity in a range of 2.5∼14.5 CeOx/nm 2 was achieved and the activity tended to decrease above 14.5 CeOx/nm 2 . The O/Ti mole ratio of TiO2 in the range of 1.32 to 1.79 showed an excellent SCR activity. It was also confirmed that the pH of the TiO2 has no effects on the SCR activity. In order to achieve excellent SCR activities, ceria oxide should be sup- ported on TiO2 possessing a high specific surface area and certain O/Ti mole ratio. In addition, the catalyst with the low CeOx surface density resulted from the high dispersed ceria oxide should be prepared.