Au nanoparticles supported on MCM-41 mesoporous silica nanospheres were fabricated through a traditional simple immersion reduction method. The obtained solid catalyst exhibited superior catalytic performance in the oxidation reaction of styrene using O-2 as an oxidant, yielding as high as 41.9% of conversion and 71.7% of styrene oxide selectivity. The solid catalyst could be reused for at least six reaction cycles without a significant decrease in the activity and selectivity. Our study supplies an active, recoverable catalyst for the green transformation of styrene.