Abstract: The ultrasonic method was used to extract the phytosterol from Paeonia suffruticosa pericarp. The ultrasonic power,the ratio of liquid to solid and the ultrasonic extraction time were assessed. A three-factor three-level orthogonal test was applied to optimize the ultrasonic extraction conditions. The results showed that the yield of phytosterol 0.495%±0.001% extracted with the optimal extraction conditions:ultrasonic power 300 W,liquid to solid ratio 30 mL/g and ultrasonic time 60 min was significant higher than the yield of phytosterol 0.439%±0.004% with the ethanol extraction conditions(p<0.05).