The composites investigated in this paper were made from wood fibers either with （polypropylene） only, or with polypropylene modified with maleic anhydride or alternatively coupled with a silane agent. The adhesion between wood fiber and polypropylene was evaluated （through） （testing） the tensile strength of the composite. An analysis was made on how the tensile strength was influenced by the ratio of wood fiber to polypropylene, as well as the effect of the addition of maleic anhydride and the silane coupling agent to polypropylene. It was found that when the polypropylene and wood fiber was mixed at 10∶3 and 3%～5% coupling agent was added to polypropylene, the wood-polypropylene composite showed the best tensile strength.