NOVELTY - Extracting and separating beta -sitosterol from Pimpinella brachycarpa, comprises extracting P. brachycarpa sample by ethanol, drying to obtain an extract, adding distilled water to form suspension, extracting with petroleum ether and ethyl acetate, stirring ethyl acetate layer and silica gel for thin layer chromatography (TLC), performing gradient elution, collecting eluent, taking beta -sitosterol standard sample and eluted fractions, collecting the retardation factor (Rf) and color spot, comparing with standard and performing crosslinked dextran gel column LH-20 separation.    USE - The method is useful for extracting and separating beta -sitosterol from P. brachycarpa.    ADVANTAGE - The method provides a foundation for research of functional components in P. brachycarpa.    DETAILED DESCRIPTION - Extracting and separating beta -sitosterol from Pimpinella brachycarpa, comprises: (a) extracting P. brachycarpa sample by ethanol, separating the extracted solution by vacuum extraction, recycling ethanol, drying until there is no alcohol smell to obtain an extract, adding distilled water (5 times of the extract) to form a suspension, extracting with petroleum ether until the solution is colorless, and extracting by ethyl acetate, (b) stirring ethyl acetate layer and silica gel for separating by thin layer chromatography (TLC), using cyclohexane-ethyl acetate (20:1 to 0:1) as an eluent to carry out gradient elution, collecting each 250 ml parts of eluent, vacuum extracting and recycling, (c) taking beta -sitosterol standard sample and fractions eluted with TLC analysis, taking petroleum ether and ethyl acetate in a ratio of 3:1, adding 5% vanillin-sulfuric acid chromogenic reagent, collecting the retardation factor (Rf) and color spot and comparing with the standard component, and (d) performing crosslinked dextran gel column LH-20 separation by collecting the above components after blow drying, adding chloroform and methanol in a ratio of 1:1 containing dissolved sample, adjusting the flow rate at 4 seconds/drop, collecting in 15 ml vials and drying to obtain white crystal.