By using dicumyl peroxide as the initiator and maleic anhydride as the monor, polyethylene was melt to graft maleic anhydride in single screw extruder. The influence order of melt index and adaptable quantity for initiator, monor and crosslinking inhibitor was decided. It was testified by infrared spectrum and graft ratio measurement that maleic anhydride has been grafted to polyethylene large molecular chain. By studying the adhesiveness of aluminum with different density polyethylene grafted maleic anhydride, we conclude that LLDPE g MAH has the higest peel strength. LLDPE g MAH blending with the flow promotor resin can be used as the hot melt adhesive in aluminum plastics compound pipe.