Abstract: OBJECTIVE To investigate the immune regulating effect of the polysaccharide from Sophora alopecuroides (SAP) in mice. METHODS The effects of SAP on the proliferation of splenic lymphocytes in mice were inspected by MTT. Nonspecific and humoral immune function of the immuno-suppression mice model which was induced by cyclophosphamide were evaluated by the carbon granular clearance test and hemolysin test. Furthermore, the carbon clearance index K, phagocytic index α and the content of hemolysin in mice serum were determined. RESULTS Different concentrations of SAP could promote the proliferation of splenic lymphocytes with various degrees in vitro. SAP could improve the immune function of mice through increasing the clearance ability, phagocytosis rate and the content of hemolysin. CONCLUSION SAP can enhance the immune function of mice through a variety of immune routes.