The invention discloses a wood-plastic composite material for 3D printing and a preparation method and application thereof. The wood-plastic composite material is mainly prepared from the following raw materials: wood flour, lignin, bamboo powder or straw powder, thermoplastic plastic, a coupling agent, a compatilizer, an antioxidant, a lubricating agent, a toughening agent and a functional additive. The composite material is good in mechanical property, excellent in lubricating property and flowability, beneficial to smooth 3D printing process, smooth in surface of a printed piece, strong ininterlayer bonding force, and excellent in wear resistance and toughness, and solves the problem of printing failure caused by high shrinkage rate and easiness in curling of polypropylene and the like; the production cost is low; the microstructure is characterized by having mutually communicated pore channels so that heat and mass transfer, ventilation and reaction are facilitated; the weight islow, and the degradation period is controllable; the material can also be used as a filler and a catalyst carrier, and has potential application prospects in the fields of filtration, adsorption, tower internals and other transfer processes, ventilation, reaction engineering and biological tissue engineering; and the material is also suitable for manufacturing lightweight accessories of unmanned aerial vehicles and automobiles and packaging materials for recycling.