Wood plastic composites (WPC) were prepared using KH-570 modified wood flour and polypropylene (PP), and the mechanical properties and aging resistance of WPC were studied. The results show that when the wood flour content is 30%, WPC with the best comprehensive properties such as mechanical properties and aging resistance can be prepared. At this time, the tensile strength and bending strength of WPC reaches their maximum values, which are 5.2% and 56.5% higher than pure PP, respectively. The tensile strength and bending strength of WPC after UV aging are 2.7% and 20.6% higher than pure PP plastic, respectively. WPC has the highest tensile strength and bending strength after water resistance, which are 3.0% and 18.8% higher than pure PP plastic, respectively. The Vicat softening temperature of WPC reaches its maximum value, which is 10 ℃ higher than that of pure PP plastic. The quality loss rate after mold corrosion resistance is 0.82%.