Abstract: Objective:To study a method for ethanol-water exchanging extraction of triterpenoids and polysaccharides from Inonotus obliquus by ultrasound thermal and cavitation technology. Methods:Shattered Inonotus obliquus, filtered them by 30 mesh filter sieve, extracted biological activity content by ethanol-water exchanging and ultrasonic technology. Results:The ethanol optimum extraction of triterpenoids was as follow:extraction temperature 30℃, time 50min, extraction times 3, the rate of liquid and solid 25∶ 1, and the best extraction was 1. 30%. The water optimum extraction of polysaccharides was as follow:extraction temperature 50℃, time 40min, extraction times 3, the rate of liquid and solid 35∶ 1, and the best extraction was 6. 96%. Conclusion:The optimum extraction which ethanol-water exchanging extraction of biological activity content from Inonotus obliquus by ultrasonic technology was steady, reasonable and improve comprehensive utilization of Inonotus obliquus effectively.