NOVELTY - The preparation method of wood-plastic composite material involves adding activated sludge into a tank, adding polystyrene pellet, stirring, sieving and washing to obtain softened polystyrene pellet, crushing wood, adding water and corn flour, stirring, adding mixing enzyme, stirring, adding ethyl acetate, heating, cooling, filtering to obtain residue, grinding residue to obtain wood fiber, mixing wood fiber, softened pellet, lubricant, foaming agent, flame retardant, and plasticizer, discharging, and drying to obtain wood-plastic powder, extruding, granulating, drying, and shaping.    USE - Preparation of wood-plastic composite material (claimed).    ADVANTAGE - The method enables the preparation of wood-plastic composite material having high wood fiber content, enhanced wood fiber and plastic binding tightness, and reinforced wood texture, at low cost.    DETAILED DESCRIPTION - The preparation method of wood-plastic composite material involves adding an anaerobic activated sludge into a treatment tank, adding polystyrene pellet with particle diameter of 3-4 mm in a ratio of 2:1-3:1, stirring at 45-50 degrees C for 20-25 minutes, aerating the bottom of tank for 6-8 hours, after 2-3 hours, sieving and washing with water to obtain softened polystyrene pellet, crushing wood into 20-40 mesh particles, pouring into fermentation tank, adding water to submerged wood particles, throwing corn flour in a ratio of 2:1, adjusting pH to 6.0-6.5 using 8-10 %mass hydrochloric acid solution, stirring, adding 5-10 %mass mixing enzyme, stirring for 10-15 minutes, adding ethyl acetate in a ratio of 1:3, heating at 35-38 degrees C for 3-4 hours, cooling to room temperature, filtering to obtain residue, grinding residue to 80-100 mesh powder to obtain wood fiber, mixing 50-60 pts. wt. wood fiber, 30-35 pts. wt. softened polystyrene pellet, 3-4 pts. wt. lubricant, 4-5 pts. wt. foaming agent, 2-3 pts. wt. flame retardant, and 1-3 pts. wt. plasticizer at 80-90 degrees C and 300-400 rpm, discharging at 110-115 degrees C, and drying to obtain wood-plastic powder, extruding and granulating, placing in oven at 70-80 degrees C for 1-2 hours, drying, and shaping. The mixing enzyme comprises amylase and cellulase in a mass ratio of 1:1. The lubricant is chlorinated ethylene wax, the foaming agent is sodium lauryl sulfate, the flame retardant comprises melamine and phenolic resin in a weight ratio of 1:1, and the toughening agent is polyazelaic anhydride.