NOVELTY - A sequoyitol is extracted and purified by crushing yew raw material, adding extracting solvent to the powder, extracting, condensing to obtain yew concentrated extract liquid, adding extracting solution to the concentrated extract, extracting taxol medicine solution and raffinate, adding flocculating agent to the raffinate, setting aside, filtering, condensing the filtrate, drying to obtain crude product, dissolving crude product in methanol, filtering, concentrating the filtrate, setting aside, and filtering.    USE - Method of extracting and purifying sequoyitol.    ADVANTAGE - The method is simple and environment-friendly, reduces production cost, and can be applied to industrial production.    DETAILED DESCRIPTION - A sequoyitol is extracted and purified by:    (A) crushing yew raw material until the grain diameter is less than 0.85 mm, adding extracting solvent having a concentration of 1 wt.% to the powder at a ratio of 3-5:1, and extracting for 3-5 times;    (B) mixing the extracts, condensing at below 80 degrees C to obtain yew concentrated extract liquid, adding extracting solution to the concentrated extract at a ratio of 1-3:1, extracting taxol medicine solution and raffinate, adding flocculating agent to the raffinate, setting aside for 6-10 hours, and filtering;    (C) condensing the filtrate, drying to obtain crude product, dissolving crude product in methanol at a weight ratio of 1:3-8, filtering, concentrating the filtrate, setting aside, filtering, and cooling the filter cake; and    (D) dissolving the filter cake in a solvent at a weight ratio of 1:2-5, adding solvent B to the mixture at a ratio of 1:1-2, stirring, setting aside, cooling at low temperature, filtering, collecting the crystals, repeating crystallizing for 3-5 times, and drying.    The extracting solvent is lower alcohol, acetone, acetonitrile or water. The lower alcohol is an aqueous solution of methanol, ethanol or propanol having a concentration of 10-50 wt.%. The extracting solution is chloroform or ethyl acetate. The flocculating agent is polyacrylamide. The volume ratio of flocculating agent to raffinate 1: 0.01-0.05. The solvent B is methanol, acetone or acetonitrile.