Actinidia arguta polysaccharide extracted by microwave was purified using a DEAE anion-exchange column,and SephadexG-100 column.The main elution fraction 0.1 brine elution was studied on the immunological activities of rat.The healthy rats were perfused with 2,10 and 20 mg/(kg·d) polysaccharides for 28 d.The effects of polysaccharide on the immune organs index,phagocytolysis of macrophage and spleen lymphocyte transformation index were determined.The results showed that,the low-dose group [2 mg/(kg·d)] of polysaccharide had almost no immunological activities.While the medium-dose group [10 mg/(kg·d)] had the obvious activities and was significant difference with the control group.Compared with the medium-dose group,the high-dose group [20 mg/(kg·d)] had no significant difference except immune organs index.