The influences of ultrasonic frequency and ultrasonic time on the extraction rate of Tannin in Elaeagnus angustifolia L. were studied. The optimizing had been got. Results showed that the ultrasonic extraction method of Tannin in Elaeagnus angustifolia L. could save time, improve extraction rates, and need not be hot. Compared with traditional extraction, the ultrasonic extraction method is a good way.