Abstract:Flavonoid was extracted from osmanthus leaves as the raw material by and ethanol-ammonium sulfate aqueous two-phase system assisted inner ebullition method.The technological conditions of extraction，including ammonium sulfate concentration，extraction temperature，and extraction time，were optimized by single-factor experiments and a response surface model.The method was compared with inner ebullition method，aqueous two-phase extraction method，and direct extraction of organic solvent.The optimal extraction conditions of flavonoid in osmanthus leaves were an ammonium sulfate concentration of 0.35 g/mL，extraction temperature of 50℃，and extraction time of 20 min.The average flavonoid yield was 2.534%.The optimized yield of flavonoid was higher than the yields obtained by the inner ebullition method，aqueous two-phase extraction method，and by direct extraction of organic solvent method in the same conditions.The results indicated the synergistic effect between aqueous two-phase method and inner ebullition method.