Abstract: KH570 and macromolecule coupling agent is used to improve the interfacial interaction of ultra-fine Kaolin particles and high density polyethylene （HDPE） blends,and a type of Kaolin/HDPE composite which has a good mechanical properties are prepared．Results show that the mechanical properties of these composites can be improved when Kaolin particles are treated with KH570 ,which the particles are less than 5％（w） of HDPE,and the optimum content of KH570 is 2％（w）．The mechanical properties of HDPE enhanced by Kaolin particles treated with macromolecule coupling agent are better than that of KH570, and the optimum content of the macromolecule coupling agent is 1％（w）．