Abstract:Literatures about ultrasonic degradation of polysaccharides reported in recent years that were re－ viewed， the effect of ultrasonic degradation on the physical properties， chemical properties and biological activ－ ity of polysaccharides were summarized， including antioxidant； antitumor； antibacterial； immunoregulatory ac－ tivity and so on. In addition， the mechanism of ultrasonic wave was analyzed at the same time， so as to provide a theoretical basis for the study and development of ultrasonic degradation of polysaccharides in the future.