Abstract: OBJECTIVE To investigate the immunomodulatory effects of the total flavonoids of broussonetia papyrifera(TFBP) on immunosuppressed mice induced by cyclophosphamide(CTX). METHODS SPF Kunming mice were randomly divided into control group, model group, and TFBP high, middle, low dosage groups(200, 100, 50 mg·kg^-1·d^-1). Except control group, the other groups were administered CTX by peritoneal injection to induce immunosuppression status. After 10 d and 30 d, the blood samples were collected to determine the number of white blood cells, phagocytosis of macrophage cells, serum IgG content, BSA antibody titers and proliferation of T and B lymphocytes. RESULTS The number of white blood cells, phagocytosis of macrophage cells, proliferation of T, B lymphocyte, BSA antibody levels and serum IgG content of the mice in TFBP groups were significantly increased(P < 0.01 or P < 0.05) in a dose-dependent manner than that of model group. Moreover, as the TFBP increased in the diets, the data above were closed to that of normal mice in control group. CONCLUSION The immune function of the immunosuppressed mice induced by CTX can be improved significanltly by TFBP administration.