Supported　Pd　catalyst　with　an　enhanced　catalytic　performance　for　polystyrene　hydrogenation　was　successfully　prepared　by　using　macroporous　silica　microspheres　(MSM)　as　the　support.　In　order　to　eliminate　the　macro　molecular　diffusion　limitation　and　improve　the　metal　utilization,　MSM　was　treated　with　steam　at　800　degrees　C　first　to　remove　mesopores　and　then　refluxed　with　aqueous　solutions　to　increase　Si-OH　groups　on　the　surface　for　Pd　immobilization.　The　optimum　support　was　obtained　after　the　steam　treatment　for　2　h　and　using　ammonia　solution　as　reflux　liquors,　and　the　corresponding　catalyst　showed　superior　hydrogenation　activity　with　a　high　conversion　of　95%.