Abstract:The total flavonoids were extracted from Daxin Kudingcha by ultrasonic assisted extraction and its content was determined by spectrophotometry with rutin as the reference substance.The effected of solid-liquid ratio，ethanol concentration，ultrasonic time and ultrasonic temperature on the extraction rate of total flavonoids were discussed by single factor experiment.The results showed that the optimal extraction conditions of ultrasonic assisted extraction method were as follows：solid-liquid ratio of 1∶25（g/mL），ethanol concentration of 70%，ultrasonic time of 15 min，ultrasonic temperature of 50℃.In this case，the extraction rate of total flavonoids was 0.772%.