Abstract: The Yunnan folk medicinal plant Cynanchum otophyllum Schnei were used as materials, and the extraction rate of Qingyangshengenin were investigated by the ultrasonic extraction process and HPLC. Based on the single factor experimental results of ethanol concentration, ultrasonic temperature and ultrasonic time, Box Behnken experimental design and response surface methodology(RSM) were selected to further analyze and optimize the extraction conditions. The finnal extraction process was hydrochloric acid concentration 0.36 mol/L, solid-liquid ratio 1∶10 (g/mL), 58% ethanol, 600 W ultrasonic power, 63 ℃ ultrasonic temperature and 33 min ultrasonic time. The optimum extraction rate of Qingyangshengenin was 0.274 5%. The experimental results are close to the predicted values of the model, indicating that the optimal process conditions are feasible.