The mechanical properties of WPC(wood plastic composite) should effected with the size of wood particle size and also characteristics of wood particles. In this paper, WPC were prepared with various size of wood particles and coupling agent and the mechanical properties were evaluated. The smaller size of wood particle were used for WPC, the higher properties of WPC in tensile strength and breaking elongation were obtained. The smaller amount of wood particle were used for WPC, the higher properties of WPC in tensile strength and breaking elongation were obtained.