Abstract: A type of solid superacid catalyst SO42-/SnO2-Ta2O5 was prepared by O/W micro-emulsion method in SDBS/ethanol/cyclohexane system, and the physicochemical properties of the prepared solid superacid samples were characterized by XRD, FT-IR and TG-DTA. The catalyst preparation conditions was optimized by orthogonal experiment and the optimum conditions were obtained as follows: a SnCl4 solution concentration of 0.1 mol/L, the mass ratios of SnCl4 solution: SDBS: ethanol: cyclohexane were 500︰1︰0.5︰15, Ta2O5/SnCl4 mass ratio of 0.06, an aging time of 24 h, the concentration of sulphuric acid impregnating solution was 3.0 mol/L and calcination at 550 ℃ for 3 h. The catalytic performance of this SO₄^2-/SnO₂-Ta₂O₅ catalyst prepared under optimum conditions was evaluated using esterification of acetic acid and n-butanol as probe reaction, its esterification rate reached 99.3%. As compared with catalyst prepared in conventional water system, catalyst prepared in SDBS micro-emulsion system exhibited better catalytic activity and stability.