Abstract: The optimal conditions for the ultrasonic-assisted extraction of total flavonoids from Prunus divaricata Ldb leave were determined using response surface methodology. Based on single factor experiments,the influence of ethanol concentration,extraction temperature and solid-liquid ratio on the extraction yield of total flavonoids were investigated.The optimal conditions were determined as follows:ethanol concentration was 51%,extraction temperature was 72 ℃,solid-liquid ratio was 1:45 (g/mL),ultrasonic power was 300 W,for 2 times,each time 30 min,the yield of total flavonoids was 38.27 mg/g,which accounts for 98.3% of the theoretically predicted value.Compared with the traditional Soxhlet extraction,the ultrasonic-assisted extraction was more convenient,less timeconsuming, higher extraction efficiency.Hence,the ultrasonic-assisted extraction can be used as an effective method for the extraction of total flavonoids from P.divaricata leave.

Key words: Prunus divaricata Ldb, total flavonoids, ultrasonic, response surface methodology