Abstract: Response surface methodology was employed to determine optimum conditions for extraction of flavonoids of beans champion. Based on the single factor experiment,ethanol concentration,solvent of ratio to material,ultrasonic power and extraction time were chosen as influencing factors,and the extraction yield of total flavonoids as response value,and then Box- Behnken central combination design were obtained.The optimal extraction conditions were determined as follows: ethanol concentration 62%,solvent of ratio to material 30∶1( m L / g),ultrasonic power 458 W and extraction time 40 min.Under these conditions,the extraction yield of total flavonoids was0.827% in comparison with the predicted yield of 0.831%.The relative error was 0.48%,which suggested that the optimal extraction conditions were reliable.