Abstract: The regenerated high-density polyethylene(HDPE), salix wood powder and waste tire rubber powder were used as the raw materials, and sulfur-containing coupling agent Si69 as the interface compatibilizer, wood powder/rubber-plastic ternary composites were prepared by molding method. The influences of Si69 on the mechanical properties and heat resistance of wood powder/rubber-plastic ternary composites were investigated, the waste tire rubber powder surface characteristics before and after Si69 modification and the microstructure of wood powder/rubber-plastic ternary composites were analyzed by FTIR and SEM. The results show that Si69 has a chemical reaction with waste tire rubber powder. When the contents of Si69 is 5wt%, the interfacial compatibility of wood powder/rubber-plastic ternary composites is better, mechanical properties and heat resistance are good, the flexural strength, flexural modulus and tensile strength are increased by 13.85%, 7.24%, 6.63%, respectively, which compared with no adding Si69; The vicat softening temperature and heat deformation temperature of wood powder/rubber-plastic composites are increased by 6.95℃ and 8.70℃, respectively. Heat resistance of wood powder/rubber-plastic composites is improved by Si69 to some extent. When the contents of Si69 is 7wt%, the notched impact strength of wood powder/rubber-plastic ternary composites can reach 3.99 k·Jm^-2.