This research use split single-screw extruder to do extrusion pretreatment of wheat straw and grade extruded straw.Respectively the mixture of pretreated wheat straw and graded wheat straw as raw materials are used to produce composite materials by the method of molding and research the impact of different levels of wheat straw on the mechanical properties of the composite materials.This research found the following: The composite materials prepared by the mixed straw were the most smoothest in surface,and ...