MSU-S (BEA) mesoporous molecular sieves with different Si/Al ratios were prepared and characterized by XRD, XRF, N 2 adsorption, 27 Al MAS NMR and NH 3 -TPD methods. Their catalytic behavior for alkylation of hydroquinone with tert-butanol was compared. MSU-S (BEA) with Si/Al ratio of 67 is a more active catalyst for the reaction in comparison with other mesoporous molecular sieves. The conversion of hydroquinone and yield of 2-tert-butylhydroquinone (2-TBHQ) on the catalyst reach 75.7% and 54.2% at 150°C, respectively. The activity correlates well with the amount of the strong acid sites on its surface. The catalyst is stable and reusable, and the product yield is only reduced by 10% after four runs. The reduction in activity is probably caused by the slow dealumination in the framework wall during reaction.