Objective:Extraction and separation of Polysaccharide from Gastrodia elata Blume（GBP-Ⅰ，GBP-Ⅱ）, study the composition of polysaccharides.Methods:The polysaccharides were extracted from Gastrodia elata Blume by hot water,respectively treated with ethanol precipitation and Sevag method,washing with organic solvent,ultrafiltration,then GBP-Ⅰand GBP-Ⅱwere obtained.GBP-Ⅰand GBP-Ⅱ were hydrolyzed with 1mol/L hdrochloric acid at 100℃,and ion chromatography was used to determinate the composition of monosaccharide of hydrolyzate.Results:GBP-Ⅰand GBP-II were both composed of rhamnose,galactose,glucose,xylose and mannose the relative contents of rhamnose,galactose,glucose,xylose and mannose of GBP-Ⅰwere 1.27%、5.41%、76.49%、6.32%、10.51%,and five monosaccharide of GBP-II were respectively 2.32%、8.49%、62.44%、10.22%、16.53%