Wood plastic composite (WPC) is very useful new material in the modern society. Improving the interfacial bond strength between wood and plastic is the foundation of improving the properties of WPC. Ethylene vinyl acetate (EVA) was used as the coupling agent of WPC in this study. Thermo-gravimetric analysis (TGA) was employed to study the thermal stability of wood flour modified by EVA. The modulus of rupture (MOR), the modulus of elasticity (MOE), and the tensile strength of WPC were investigated to understand the effects of the vinyl acetate (VA) content and the melt index of EVA on WPC. The results show that EVA could improve the thermal stability of wood flour and the mechanical properties of WPC. The mechanical properties of WPC are increasing with VA content raise and melt index reducing.