The ultrasonic assisted extraction of total flavonoids from Crataegus pinnatifida Bge.var.major N.E.Br. Fruit was used to optimize the extraction process, and its antioxidant capacity was measured. [Methods]On the basis of single factor experiment, the response surface experiment was designed with ethanol concentration, liquid-solid ratio, extraction time and temperature as independent variables, and the extraction rate of total flavonoids as a response value. [Results]The optimum extraction process was as follows: ethanol concentration 62%, liquid-solid ratio 26 ml / mg, extraction time 21 min, extraction temperature 52 ℃, and the highest extraction rate was 10.19%. [Conclusion]The antioxidant activity showed that the total flavonoids had significant antioxidant capacity.