The paper is mixing the raw materials of wheat straw as enhanceosome and highdensity polyethylene/pohyprpylene (HDPE/PP) of thermoplastic to produced wood-plastic composite by adopting extrusion way and researching effect about the content of HDPE and PP on the properties of composite. Under a certain conditions，the high-speed mixer mixed the compound of wheat straw powder and thermoplastics and other auxiliaries，and then the compound were melting prilling by twin-screw extruder followed and molding by the single screw extruder.The mechanical properties of composite of wheat straw and thermoplastic were measured .The results indicated that adding a small amount of wheat straw powder caused the reduction of mechanical properties of wood plastic composite，the mechanical properties of wood plastic composite increased with increasing wheat straw powder content，mechanical properties decreased when the content of wheat straw was more than a certain percentage，especially，the impact property decreased obviously；the test indicated that the mechanical properties of HDPE were higher than PP.