The optimum extracting condition of flavonoids from chrysanthemum is studied in this article.The optimum condition with alcohol-water backwatering system is C 3 B 3 A 1 ,that's to use1volume of 80%alcohol to extract for 3times (2h /times).And with Ultrasonic treatment ,the results showed that 60:1of 80%ethanol to douse the dried chrysanthemum flower for 24hours,and ultrasonic treatment lasts for 15minutes.The content of flavonoid in the extraction liquid was as hig h as 9.60%.