Abstract: Two kinds of ultra high molecular weight polyethylene (UHMWPE)/Kaolin composites were prepared by means of melt mixing and polymerization filling, respectively. The erosion wear characteristics of the two kinds of UHMWPE/Kaolin composites and their relationships with the velocity of a sand slurry were investigated on an erosion wear tester. The wear mechanisms of the composites were discussed through examining and analyzing the worn surfaces with a scanning electron microscope. It has been found that the UHMWPE/Kaolin composite of about 6.6% (mass fraction) kaolin prepared by polymerization filling has much better erosion wear properties than UHMWPE and is thus a promising structural material candidate for engineering application.