Abstract: Aqueous two- phase cooperated with microwave methods were applied to explore the extraction technology of total flavonoids in Platycodon grandiflorum stems and its antioxidant ability in vitro was studied.First,the extraction technology was optimized by single factor and orthogonal test,while the scavenging activity of total flavonoids extraction solution to DPPH· and ·OH were measured by spectrophotometric method.When the ratio between material and solvent,the microwave power,the ratio between ethanol and water,the extraction time and the mass concentration of ammonium sulfate were 1 ∶ 40( m / v),500 W,0.8 ∶ 1,5 min and 0.30 g / m L respectively,the much higher average extraction yield of total flavonoids could reach about 0.793%.The activity test had shown that total flavonoids solution extracted from Platycodon grandiflorum stems had strong scavenging activity to DPPH· and ·OH,and the scavenging activity might gradually be enhanced with the increase of mass concentration of total flavonoids in extraction solution.