Abstract: Ethanol aqueous solution was used to extract total flavonoids from tea under ultrasonic assistance.To optimize extraction yield of total flavonoids, response surface methodology(RSM) was employed to perform it.The optional values of variables were as follows: ultrasonic treatment time 35.30 min, solid/liquid ratio 1∶15.40, ethanol concentration in aqueous solution 60.6%, ultrasonic power 557.83 W, the total flavonoid yield obtained under such conditions was 8.513 mg/mL, which was extremely consistent with the experimental value with a relative error of 0.6%.