As a unique type of millet in Shanxi, "Qin zhou huang" was extensively studied for improving its comprehensive utilization and the separation efficiency of flavonoids.In this paper, the ultrasonic-assisted aqueous two-phase system was studied and used to extract flavonoids from "Qin zhou huang".After orthogonal experimental optimization, the flavonoids content could reach the maximum of 8.56 mg/g under the following conditions: acetone concentration 31%, (NH4)2SO4 concentration 19%, solid-liquid ratio 1∶40, temperature 40 ℃ and ultrasonic time 30 min.Meanwhile, the effects of common processing methods on the millet flavonoids were also studied, the results showed that cooking or steaming at short time (<15 min) was the most ideal processing method, because the loss of flavonoids contents was relatively small.Besides, the flavonoids contents of all samples decreased as processing time extended, and the preferred method was boiling > steaming> braising>frying.Moreover, the antioxidant activities of millet flavonoids were determined, the results showed that DPPH scavenging capacity, hydroxyl radical scavenging capacity and reducing power were all increased as substrate concentration increased and it is a dose-dependent reaction.Overall, millet flavonoids has good antioxidant activities.