NOVELTY - Separating water chestnut shell involves drying and crushing the chestnuts skin to obtain powder. The powder is added in extraction tank comprising extraction solvent to extract at 50-80 degrees C for 1-3 hours. The mixture is extracted 2-3 times, filtered, and the filtrate is concentrated under reduced pressure to obtain a paste. The extract (1 parts) is dispersed in 5-8 parts water to obtain a turbid solution. The solution is extracted three times with 1-2 times with ethyl acetate and water. The volume of combined extracts is concentrated to obtain extracts in low pressure.    USE - Method for separating water chestnut shell (claimed).    ADVANTAGE - The method enables to separate water chestnut shell in simple and economical manner with high product purity by turning waste into useful material. The method enables large-scale production and has broad prospects for development.    DETAILED DESCRIPTION - Separating water chestnut shell involves drying and crushing the chestnuts skin to obtain powder. The powder is added in extraction tank comprising extraction solvent to extract at 50-80 degrees C for 1-3 hours. The mixture is extracted 2-3 times, filtered, and the filtrate is concentrated under reduced pressure to obtain a paste. The extract (1 parts) is dispersed in 5-8 parts water to obtain a turbid solution. The solution is extracted three times with 1-2 times with ethyl acetate and water. The volume of combined extracts is concentrated to obtain extracts in low pressure. The extract is dissolved in methanol. The samples of silica gel are added and solution is separated by silica gel column chromatography, eluting with an organic solvent, performing thin layer chromatography and collecting the fractions containing betulinic acid. The eluate is concentrated under reduced pressure to obtain a crude product. The crude product is dissolved in hot methanol or ethanol. The crystals are precipitated by adding water. The crystals are crystallized, filtered, recrystallized, again filtered and dried to obtain 97% betulinic acid crystals.