Abstract: The aims were to investigate the best technological condition to extracting flavonoids from cumin, and to investigate the antioxidant activity of flavonoids. By using Ultrasonic-aided extraction, the effects of solvent strength, the ratio of material to solvent, the time of extraction, the power of extraction were obtained. L9(34) orthogonal experimental design was used to investigate the better condition of extraction. Total reducing power and DPPH method were used to study the antioxidant activity of cumin. The optimal extraction condition were solvent 70% ethanol, the ratio of material to solvent was 1:35, the time of extraction 80 min, the power of extraction 125 W. Orthogonal effects of flavonoids in the yield factors were: the power of extraction, the ratio of material to solvent , solvent strength, the extraction time. The result of Antioxidant activity experiment showed that cumin had a good reducibility, and the effect on DPPH free radical scavenging was obviously, the IC50 was 0.109 mg/mL. Ultrasonic extraction was a kind of feasible extraction method, as antioxidant, the cumin of Xinjiang had a great value of development and application.