The invention relates to a wood plastic composite, in particular relating to a wood plastic composite dalle and a preparation method thereof. The preparation method comprises the following steps: mixing polrvinyl chloride particles, nano attapulgite, calcium carbonate powder, short glass fibers, terpene resin, chlorinated polyethylene, tribasic lead sulfate and stearate, extruding and pelleting, so as to obtain a modified plastic particle; evenly mixing the modified plastic particle with wood poader and azodicarbonamide and pelleting so as to obtain a wood plastic particle; and finally, extruding the wood plastic particle, foaming and forming so as to obtain the wood plastic composite dalle. The wood plastic composite dalle can be manufactured conveniently, and has the advantages of high production mechanization degree and less required labor. Compared with the common plastic dalle, the wood plastic composite dalle provided by the invention has the following advantages: the plastic dosage of the wood plastic composite dalle is reduced, and wood plastic composite dalle is environment-friendly, and has the characteristics of high modulus, low density, creepage resistance and low product cost. Compared with the gypsum boards, aluminum plates and the like, the wood plastic composite dalle provided by the invention has the following advantages: the cost is lower, the density is smaller, the installation and maintenance are more convenient, and the wood plastic composite dalle has an air purification function. The wood plastic composite dalle can be widely applied to various scenes such as buildings and houses, home offices and the like.