NOVELTY - A polyphenol is extracted from Castanea mollissima blume shell by filling blume shell powder with particle degree of 5-60 meshes in a percolating column, pressing, adding extraction solvent, dipping for 0.2-1 hour at 30-70 degrees C, flowing the extraction solvent via the percolating column from top to bottom, collecting percolating-filtering solution, and decompressing and concentrating to obtain percolating solution; and decompressing and concentrating percolating-filtering solution to remove alcohol and obtain concentrated polyphenol crude extraction solution.    USE - Method for extracting polyphenol (claimed) used as antioxidant for food and pharmacy industry.    ADVANTAGE - The method obtains high polyphenol of good quality. The extraction rate is above 60% and the production process is simple with low cost. It has no pollution and is suitable for industrialization production.    DETAILED DESCRIPTION - Extracting polyphenol from Castanea mollissima blume shell, comprises (A) ventilating and drying C. mollissima blume shell in shade, breaking, sieving and removing floccules in the shell by sieving; (B) filling blume shell powder with particle degree of 5-60 meshes in a percolating column, pressing and measuring volume of pilled shell, adding extraction solvent, dipping for 0.2-1 hour at 30-70 degrees C, flowing the extraction solvent via the percolating column from top to bottom, collecting percolating-filtering solution, and decompressing and concentrating to obtain percolating solution; (C) decompressing and concentrating percolating-filtering solution to remove alcohol and obtain concentrated polyphenol crude extraction solution; (D) pumping the polyphenol crude extraction solution into balanced macroporous adsorption resin, using distilled water and alcohol to elute polyphenol, and collecting elution solution; (E) decompressing and concentrating the elution solution; and (F) freezing and drying, or atomizing and drying the concentrated polyphenol solution to obtain C. mollissima blume shell polyphenol powder.