Abstract:The polysaccharide of Polygala fallax Hemsl.（PFP） was extracted using the method of water extraction and alcohol precipitation.After deproteinization by Sevag method and decoloration by active carbon，PFP1 and PFP2 were obtained by Sephadex-G75 column chromatographygel，and the PFP1 was characterized by infrared spectrum（IR），gel permeation chromatography（GPC）and 1-phenyl-3-methyl-5-pyrazalone（PMP）pre-column derivatization high performance liquid chromatography （HPLC）method.The results show that weight -average Mw of PFP1 was 20 794 Da with a polydispersity index of 1.32，and it was a heteropolysaccharide and composed of mannose，glucuronic acid，rhamnose，glucose，galactose，arabinose and with a molar ratio of 0.09∶1∶0.48∶0.64∶0.71∶0.35.Additionally，in vitro antioxidant activity assays suggested that PFP1 presents scavenging activity toward DPPH radical，hydroxyl radical，superoxide anion radical and ABTS＋radical in a dose-dependent manner，which contributes to an intensive development and research of PFP.