A　series　of　condensed　ethylene　glycol　acrylate　monomers　with　different　molecular　weight　was　grafted　to　polyethylene　films　by　means　of　preirradiation.　The　effect　of　the　molecular　weight　of　monomer　and　co-solvent　system　on　the　grafting　reaction　and　the　properties　of　the　grafted　sample　were　studied.　The　experimental　results　showed　that　the　initial　rate　of　grafting　reaction　decreased　and　the　molar　degrees　of　grafting　linearly　decreased　with　the　increment　of　molecular　weight　of　the　monomer.　The　grafting　degree　was　increased　with　the　swelling　degree　of　the　grafted　film.　The　biocompatibility　and　blood　compatibility　of　the　grafted　PE　films　were　evaluated　by　the　determination　of　hydrophilicity　and　anti-thrombus.