Abstract:Flos sophorae immaturus（ FSI） was taken as raw material，from which flavonoids were extracted using an ultrasound-assisted aqueous two phase system. With the FSI flavonoid extraction yield as the target index，the optimal extraction process was optimized by single factor and response surface experiments，while the antioxidant and hypoglycemic activities of FSI flavonoid were investigated in vitro. The optimal extraction process of FSI flavonoids was as follows：ultrasonic power 600 W，ultrasonic time 12 min，mass fraction of（NH4）2SO4 21%，mass fraction of polyethylene glycol 6000（ PEG 6000） 16%，material-liquid ratio 1∶20（ g/mL）.Under these conditions，the extraction yield of flavonoids from FSI reached 10.58%. Half maximal inhibitory concentration（ IC50） of FSI flavonoids against ABTS+ and DPPH free radicals were 9.20，5.06 μg/mL，respectively. The IC50 of the inhibitory rate of FSI flavonoids on α-glucosidase and α-amylase was 22.64，194.96 μg/mL，respectively. It demonstrated ideal inhibitory effects，indicating potential antioxidant and hypoglycemic activities of FSI flavonoids in vitro.