Palladium catalyst supported on SO3H-functionalized SBA-15 ( denoted as Pd/SO3H-SBA-15) was applied to the direct synthesis of hydrogen peroxide from hydrogen and oxygen. For comparison, palladium catalyst supported on SBA-15 (denoted as Pd/SBA-15) was also employed for the direct synthesis of hydrogen peroxide. Selectivity for hydrogen peroxide, yield for hydrogen peroxide, and final concentration of hydrogen peroxide over Pd/SO3H-SBA-15 catalyst were much higher than those over Pd/SBA-15 catalyst. The high catalytic performance of Pd/SO3H-SBA-15 catalyst was attributed to the enhanced acid amount of SO3H-SBA-15 support, which served as an alternate acid source in the direct synthesis of hydrogen peroxide from hydrogen and oxygen.