A series of mesoporous V/DMDS-x/SBA-15 catalysts with different silylation degree were prepared by post-grafting of dimethyldichlorosilane (DMDS) onto SBA-15, followed by introduction of vanadium species via impregnation method. The silylated sample showed better catalytic activity than the non-silylated one in both styrene epoxidation and benzene hydroxylation reactions. Styrene conversion of 67.1% and styrene oxide selectivity of 88.5% with tert-butyl hydroperoxide (TBHP), and benzene conversion of 34.1% and phenol selectivity of 93.2% with H2O2 were obtained over the V/DMDS-1.0/SBA-15 catalyst. The considerably improved activity was attributed to the optimized affinity between the catalyst surface and the reactants.