The effects of V2O5 loading of the V2O5/TiO2 SCR catalyst on SO2 oxidation activity were examined by infrared spectroscopy (DRIFT) and SO2 oxidation measurement. Vanadium oxide added to the catalyst was found to be well dispersed over the TiO2 carrier until covered with monolayer V2O5 The rate of SO2 oxidation increased almost linearly with V2O5 loading below the monolayer capacity and attained saturation with further increase. The hydroxyl groups bonded to vanadium atoms, V-OH, might be altered by SO2 oxidation. Both V=O and V-OH groups are likely involved in the adsorption and desorption of SO2 and SO3.