A　novel　method　for　the　surface　modification　of　PVDF　porous　membranes　was　introduced.　Styrene-(N-(4-hydroxyphenyl)　maleimide)　alternating　copolymer　SHMI-Br　was　blended　with　PVDF　to　fabricate　SHMI-Br/PVDF　membranes.　The　C-Br　bond　on　the　SHMI-Br/PVDF　membrane　was　served　as　initial　site　of　ATRP,　and　P(PEGMA)　brush　was　grafted　on　the　PVDF　membrane.　Attenuated　total　reflectance-Fourier　transform　infrared　spectroscopy　(ATR/FTIR)　was　used　to　prove　the　P(PEGMA)　brushes　were　successfully　grafted　onto　the　SHMI-Br/PVDF　membrane　surface.　Introduction　of　P(PEGMA)　brushes　on　the　PVDF　membrane　surface　enhanced　the　hydrophilicity　effectively.　When　the　PEGMA　degree　of　grafting　was　16.7　wt%,　the　initial　contact　angle　of　PVDF　membrane　decreased　from　98A　degrees　to　42A　degrees.　The　anti-fouling　ability　of　PVDF　membrane　was　improved　significantly　after　P(PEGMA)　brush　was　grafted.　Taking　the　PEGMA　degree　of　grafting　16.7　wt%　as　an　example,　the　flux　of　protein　solution　was　about　151.21　L/(m(2)　h)　when　the　pH　value　of　the　BSA　solution　was　4.9.　As　the　pH　value　was　increased　to　7.4,　the　flux　was　changed　to　180.06　L/(m(2)　h).　However,　the　protein　solution　flux　of　membrane　M3　(PEGMA:　0　wt%)　was　only　73.84　L/(m(2)　h)　and　113.52　L/(m(2)　h)　at　pH　4.9　and　7.4,　respectively.