Ultrasonic-enhanced supercritical fluid is an effective method to remove caffeine from green tea.Among the 5 factors,the extraction pressure has the highest impact,and the temperature has the lowest impact.The optimum conditions for removal of caffeine from green tea were pressure at 30MPa,temperature at 55C,time in 4h,moisture content 30%,and ultrasonic power of 100 watt. Ultrasonic-enhanced supercritical fluid is expected to offer a new way for the production of low-caffeine or caffeine-removed tea