The invention relates to a compound foamed plastic-wood composite material plate and a preparation method thereof. The preparation method comprises the following steps: adding polyvinyl chloride and dibasic lead phosphite into a stirring kettle, and evenly mixing at high temperature; adding wood powder, kaolin powder, accelerator, azobisformamide, calcium stearate and chlorinated polyethylene into the stirring kettle, heating, evenly mixing, and cooling; adding o-toluenesulfonhydrazide and dibutyl phthalate into the kettle, heating, evenly mixing, cooling, taking out the mixture, and granulating by extrusion; and after finishing the granulation, carrying out extrusion molding on the granules. The invention has the advantages of high manufacturing convenience, low cost, light weight, low brittleness, excellent ductility, excellent shock resistance, favorable surface tactile sensation, sound insulation, heat insulation, aging resistance, discoloring resistance and no buckling deformation, is convenient to mount and maintain, and can adsorb toxic gas; and the invention consumes less plastic, is environment-friendly and can be recycled. The invention can be used in office buildings, families and other occasions, and can be made into door plates, photo frames, picture frames, skirting plates, suspended pinch plates, suspended beams, pergolas and the like.