Abstract: OBJECTIVE　To explore the effects of the Radix Ranunculi Ternati polysaccharide(RRTP) on immunological function of the immunosuppressive model mice induced by cyclophosphamide(CY). METHODS Establish the immunosuppressive model mice by using injection of CY. The effects of RRTP on model mice were observed following these indexes, such as peritoneal macrophage phagocytosis function, formation of hemolysin or plaque, and lymphocyte transformation. RESULTS The large and medium dose RRTP group can increase phagocytosis percentage and phagocytic index of peritoneal macrophages in immunosuppressive model mice significantly. The medium dose RRTP and lentinan group can promote the formation of hemolysin significantly. The large, medium and small-dose RRTP, and lentinan group can promote the formation of plaque and lymphocyte transformation significantly. CONCLUSION The RRTP can obviously improve immunological function of the immunosuppressive model mice induced by CY.