Abstract:The extraction of favonoids from the leaves of Platycladus orientalis was carried out by ultrasonic assisted method.The effects of ultrasonic time，temperature and frequency on the yield of flavonoids were investigated by single factor test.On the basis of single factor experiment，response surface method was used to optimize the extraction process.The results showed that the optimum conditions of extraction of total flavonoids from the leaves of Platycladus orientalis were ultrasonic time 51 min，ultrasonic temperature 60 ℃，ultrasonic frequency 40 kHz，and the yield of flavonoids was（26.350±0.065）mg/g.