Tungsten-promoted zirconia (WO3/ZrO2) nanoparticles were synthesized in reverse micelles of water/sodium bis(2-ethylexyl) sulfosuccinate/isooctane, which were compared with WO3/ZrO2 prepared by incipient wetness impregnation and sot-gel method. The control of particle size was achieved by varying the process variables, such as water-to-surfactant molar ratio and reagent concentration. Their sizes, appearances, crystal structures. and thermochemical behavior were characterized by UV-vis, TEM, XRD and TG-DTA. NH3-TPD and Hammett indicator measurement were also employed to study the acidity of samples. The results revealed that samples prepared in reverse micelles had higher percentages of T-ZrO2 and greater acid strength than those of other samples. The alkylation of butene with isobutane on WO3/ZrO2 was carried out in a fixed-bed reactor. Samples synthesized in reverse micelles had better reaction performance than others. A parallel relationship could be drawn between the catalytic activity and the acid amounts as well as the acid strength of the catalysis. (C) 2003 Elsevier Inc. All rights reserved.