Fuente: WIPO "hemp" The invention belongs to the technical field of high polymer materials and injection molding, and relates to a preparation method of modified hemp stem core powder, which comprises the following steps: crushing and ball-milling waste hemp stem cores, and carrying out chemical treatment with alkali, a silane coupling agent and the like to prepare the modified hemp stem core powder; then the modified hemp stem core powder, polypropylene, inorganic nano powder, a plasticizer, an antioxidant and the like are subjected to high-speed mixing, melt grafting blending extrusion and pelletizing to prepare modified hemp stem core powder/polypropylene composite material granules, and finally a sample is obtained through injection molding. The preparation process is simple, the added value of the hemp stem core powder is improved, the use of polypropylene is reduced, and the environmental pollution is reduced. The prepared modified hemp stem core powder/polypropylene composite material not only has good mechanical properties, corrosion resistance and processability, but also has the characteristics of environmental protection, strong wood texture and the like, can be used for replacing a common PP material for injection molding, and can be widely applied to the fields of toys, outer packaging boxes, personalized artworks and the like.