Solid super acid SO42-/SnO2-Al2O3 was prepared via co-condensation method and characterized by powder X-ray diffraction (XRD), isothermal nitrogen adsorption/desorption, Fourier-transform infrared spectroscopy (FT-IR), and Thermogravimetric analysis (TGA). The influences of introducing aluminum on its structure and surface properties and the catalytic activity for acylation of methyl-phenate have been investigated. As a result, the introduction of appropriate amount of aluminum would increase the number and the intensity of the attached-on-surface sulfuric groups and thus increase the specific surface area and catalytic activity. (C) 2008 Elsevier B.V. All rights reserved.