Abstract: To study the influences of soybean polysaccharides combined with cyclophosphamide on immune system and hematopoietic system.This experiment with axillary inoculated S180 sarcoma of KM mice as the carrier, intraperitoneal injection of cyclophosphamide 25 mg /kg·d and soybean polysaccharides 50, 100 and 200 mg /kg·d respectively.The amount of peripheral blood leukocyte of mice were counted; TNF-α was determined by ELISA and splenic lymphocyte surface value of CD+4/CD+8was detected by flow cytometry.The results showed that groups treated with soybean polysaccharides could improve the leukocyte in peripheral blood of tumor- burdened mice and improve the level of cytokine TNF-α in peripheral blood compared with cyclophosphamide model group.The results showed that the quantity of CD+4cells changed inconspicuously with the increasing of soybean polysaccharides, the quantity of CD+8cells decreased and the value of CD+4/CD+8rised. So soybean polysaccharides could enhance anti- tumor effect of cyclophosphamide, strengthen the immune function and lighten toxicity of tumor-burdened mice.