Abstract: Taking the stems and leaves of Pithecellobium clypearia（Jack） Benth. as experiment materials, the total flavonoids and gallic acid were extracted by ultrasonic assisted extraction method. On the basis of single factor experiment, the extraction process was optimized by response surface methodology. The results showed that the order of influence of different factors on extraction of total flavonoids from Pithecellobium clypearia（Jack） Benth. was ratio of material and liquid > ultrasonic power > ultrasound time > ethanol concentration. The optimal extraction condition was ratio of material and liquid 1∶90, ethanol concentration 75%, ultrasonic power 170 W and ultrasound time 40 min. Under this condition, the yield of total flavonoids was 2.29% （theoretical value 2.37%）. The order of influencing factors on gallic acid extraction was ethanol concentration > ratio of material and liquid > ultrasound time. The optimal extraction condition was ratio of material and liquid 1∶70, ethanol concentration 65% and ultrasonic time 60 min. Under this condition, the extraction rate of gallic acid was 5.98% （theoretical value 6.04%）. The model established in this study had a good fitting effect, and the experimental values were highly correlated with the fitting values, which had strong guidance for the extraction of total flavonoids and gallic acid from Pithecellobium clypearia （Jack） Benth., and could provide a scientific basis for the subsequent research.

Key words: Pithecellobium clypearia （Jack） Benth., total flavonoids, gallic acid, ultrasonic assisted method, response surface optimization