Graft　copolymerization　of　maleic　anhydrideon　(MAH)　onto　enzymatic　hydrolysis　lignin　(EHL)　was　carried　out　with　sodium　hydroxide　aqueous　solution　as　solvent　and　potassium　persulfate-sodium　bisulfite　(K2S　2O8-NaHSO3)　as　initiator.　The　graft　ratio　and　graft　efficiency　of　the　copolymer　were　systematically　investigated　through　changes　in　the　reaction　temperature,　reaction　time,　MAH　concentration　and　initiator　concentration.　The　grafted　copolymer　was　further　characterized　by　FTIR　and　UV-visible　spectroscopy.　It　was　found　that　the　graft　ratio　and　graft　efficiency　varied　significantly　with　the　above-mentioned　reaction　parameters.　The　optimum　conditions　for　the　graft　copolymerization　were　as　follows:　initiator　K2S2O8-NaHSO3　with　a　quantity　2.5%　of　lignin,　MAH′.　EHL　(mass　fraction)　=　0.12,　reaction　time　was　3.5h　and　temperature　at　60°C.　In　the　scope　of　this　experiment,　the　graft　ratio　and　graft　efficiency　were　respectively　obtained　up　to　5.34%　and　80.08%.　The　fact　verified　that　EHL　has　better　chemical　activity.　©　2010　American　Institute　of　Physics.