Abstract: Increasing attentions have been paid to the natural polysaccharides because of their numerous bioactivities,such as anti-tumor,enhance immunity and antioxidant.The isolation and purification were the primary process for the further study on the structure and bioactivity of natural polysaccharides.In this paper,the isolation of natural polysaccharides in ways of traditional hot water extraction,enzymatic extraction,ultrasonic assisted extraction,supercritical fluid extraction,ultrahigh pressure extraction technology,microwave assisted extraction and aqueous two-phase extraction were comprehensively introduced.In addition,the further separation and purification methods were also reviewed based on mechanism of the purify process,including physical separation,intermolecular force and chemical purification.It provided foundational and valuable reference information for further investigation and efficient utilization of natural polysaccharides.

Key words: natural plants, polysaccharides, extraction, purification