NOVELTY - Extracting high content of resveratrol from Polygonum cuspidatum, involves (a) crushing giant knotweed, (b) adding water and zymolyte, and subjecting mixture to enzymolysis process, (c) extracting, and concentrating and cooling product, (d) centrifuging and filtering product, (e) adding the filtrate in column, eluting column, decompressing and concentrating eluent, and cooling product to generate light yellow crystal, and (f) drying crystal to obtain the resveratrol.    USE - The method is useful for extracting high content of resveratrol from P.cuspidatum.    ADVANTAGE - The method is cost-effective and improves yield of products. The purifying process is simple to perform. The problem of traditional method on repeated crystallizing or high-cost column chromatography can be solved. The high-content resveratrol can be obtained by coating on column once. The enzymolysis can be completely carried out within 24 hours, and hence the production cycle is greatly reduced. The adopted solvent includes ethanol and water, hence pollution can be avoided, and safe production can be ensured.    DETAILED DESCRIPTION - Method for extracting high content of resveratrol from Polygonum cuspidatum, involves (a) crushing raw medicine material of giant knotweed into 5-20 meshes using traditional Chinese medicinal crusher, (b) adding 1-5 times of water to the crushed product, adding zymolyte to the obtained mixture, stirring the obtained mixture, and subjecting the obtained mixture to enzymolysis process for 24 hours at 30-40 degrees C, where the zymolyte is Saccharomyces cerevisiae, vegetable hydrolytic enzyme, cellulase or their mixtures, (c) adding ethanol (50-90%) to the obtained product, heating, refluxing and extracting for 1 hour, extracting for three times, combining the three extracting liquids, recycling ethanol, concentrating the medicinal solution, and cooling the concentrated product, (d) centrifuging the obtained product, standing and cooling the obtained liquid, and filtering the liquid to obtain filtrate, (e) adding the filtrate directly in resin column, firstly eluting the column using water, where concentration of the resin is 3-10 vol.%, eluting the column using 40-90% ethanol, collecting ethanol eluent, recycling ethanol, decompressing and concentrating the eluent, and cooling the obtained product to generate light yellow crystal, and (f) drying crystal, washing the crystal using clean water at 60 degrees C for 1-5 hours, and drying the obtained product to obtain the resveratrol (white product).