V2O5 and WO3 supported on TiO2-SO42- have been characterized by BET, XRD, XPS, TPD and H-2-TPR measurements. The comparison of the reactivity on SCR reaction of the catalysts with the support allows to understand the interaction of sulfate species with V2O5 and WO3. The sulfate deposited on TiO2 does not affect on its physical properties such as surface area and phase transformation. In TPD and HZ-TPR, it is found that the sulfate stability strongly depends on the loaded metal oxides and the reduction property of V2O5 in ternary sample is changed due to the synergetic effect between V2O5 and WO3. The SCR reactivity of V2O5/TiO2-SO42- at low temperature becomes the same as that of V2O5-WO3/TiO2-SO42-, while at high temperature, the high NO conversion of V2O5-WO3/TiO2-SO42- is extended up to 450 degreesC. Accordingly, it can be suggested that the strong interactions among the supported components on TiO2 play important roles in the modification of the SCR reactivity over TiO2-based catalyst.