A series of catalysts, NiSO4/TiO2-ZrO2 having different TiO2-ZrO2 composition, for acid catalysis was prepared by the impregnation method using an aqueous solution of nickel sulfate. The addition of TiO2 to ZrO2 improved the surface area of the catalyst and enhanced its acidity remarkably because of the formation of new acid sites through the charge imbalance of Ti-O-Zr bonding. The binary oxide, TiO2-ZrO2 calcined above 600 degrees C resulted in the formation of crystalline orthorhombic phase of ZrTiO4. Therefore, NiSO4/TiO2-ZrO2 calcined at 500 degrees C exhibited a maximum catalytic activity for acid catalysis, and then the catalytic activity decreased with the calcination temperature. The correlation between catalytic activity and acidity held for both reaction, 2-propanol dehydration and cumene dealkylation. NiSO4 supported on 50TiO(2)-50ZrO(2) (TiO2/ZrO2 ratio = 1) among TiO2-ZrO2 binary oxides exhibited the highest catalytic activity for acid catalysis.