Solid superacids SO42-/ZrO2 and SO42-/TiO2 were applied in the alkylation of isobutane with butenes at a reaction temperature of 100-degrees-C. They showed high activity, selectivity and stability. The nature of the superacid sites was discussed based on IR, X-ray diffraction, and measurement of the acidic properties of the catalyst. An amorphous support was essential for preparing effective catalysts. The optimal calcination temperatures were 650-degrees-C and 550-degrees-C for SO42-/ZO2 and So42-/TiO2, respectively. The catalytic activity correlates well with the acid strength of the catalyst. Activation of isobutane over the solid superacid was observed at 100-degrees-C.