NOVELTY - Preparation of polysaccharide involves heating 50-95% lotus plumule medicinal material to ethanol, reflowing and extracting, combining the extracted solutions, filtering, decompressing and concentrating the filtrate to medicine material, obtaining extract, extracting dregs of decoction, drying, volatilizing the ethanol, then reflowing and extracting using distilled water, obtaining water decoction solution, stirring uniformly, centrifuging, vacuum drying, eluting the strong-acid cation exchange resin, collecting the eluent, reducing the pressure, condensing and drying.    USE - Preparation of polysaccharide (claimed).    ADVANTAGE - The polysaccharide is efficiently prepared without polluting the environment, by a simple method.    DETAILED DESCRIPTION - Preparation of polysaccharide involves heating 50-95% lotus plumule medicinal material to ethanol, reflowing and extracting for 1-3 hours, adding 3-5 times ethanol in the traditional Chinese medicinal materials and acetylacetic ether, then combining the extracted solutions, filtering, decompressing and concentrating the filtrate to medicine material in the weight ratio of 0.5-2 times, obtaining extract, extracting dregs of decoction, drying, volatilizing the ethanol, then reflowing and extracting using distilled water for 3 times for 1-3 hours, combining the extracting solutions, filtering, decompressing and concentrating the filtrate to medicine dregs for 0.5-2 times, obtaining water decoction solution, processing water solution through clarifying agent, centrifuging, providing supernatant fluid of 95% ethanol, stirring uniformly, centrifuging, vacuum drying, obtaining lotus plumule polysaccharide, concentrating obtained extract, filtering, concentrating the filtrate as sample solution, absorbing the sample solution by strong-acid cation exchange resin, washing using distilled water, removing water-soluble impurity, eluting using 50-95% ethanol under flow rate of 3 BV/hour, collecting the eluent, reducing the pressure, condensing and drying, obtaining alkaloid of lotus plumule flavone, eluting the strong-acid cation exchange resin with 1-5 vol% ammonia water, collecting the eluent, reducing the pressure, condensing and drying.