Wells-Dawson type 18-tungstophosphoric acid (H 6 P 2 W 18 O 62 ) as guest was encapsulated inside the nanocages of mesoporous SBA-16 host. The pore entrance of SBA-16 material was modified by silylating reagent to prevent the escape of encapsulated H 6 P 2 W 18 O 62 from the nanocages. The prepared host-guest material was characterized by different physicochemical techniques. X-ray diffraction and transmission electron microscopy analyses indicated the retention of mesoporous structure of SBA-16 and well-dispersion of the H 6 P 2 W 18 O 62 into the nanocages of SBA-16. The obtained material exhibited high catalytic activity, stability, and recyclability in the epoxidation of olefins and oxidation of alcohols in the presence of H 2 O 2 as oxidant.