Abstract: Recent years,due to their security and efficient immune competence,plant polysaccharides have been widely concerned by scholars at home and abroad.What’s more,most plant polysaccharides with immunomodulatory effects were natural immune regulators,with the promotion of immune organ growth,activation of immune cells,activation the complement system,cytokines release and other immune regulatory functions.This review summarized the research progress on the immune regulatory effects of plant polysaccharides on the three levels of tissues:organs,cells and molecules,and the immunomodulatory mechanisms of polysaccharides from receptors,signaling pathways and microRNA.Aimed to summarize the research status and prospect the research direction of the current plant polysaccharide immunomodulatory effects and mechanisms,and pointed out the shortcomings in the current research,then provided ideas for the study of the deeper mechanism of plant polysaccharide immunomodulation,and provided a scientific reference for the development of new plant polysaccharide immunomodulatory drugs.

Key words: plant polysaccharides, immunomodulatory effects, macrophages, cytokines, microRNA