Abstract: Objective To investigate the immunoregulation effect of Sulforaphane(SF) in immunosuppression mice. Methods Institute of Cancer Research (ICR) mice were randomly divided into four groups: control group, Cyclophosphamide(Cy) model group, SF high-dose(30mg/kg) group and SF low-dose(15 mg/kg) group. The phagocytosis of macrophage, the content of serum hemolysin, lymphocyte transformation rate, spleen index and thymus index were analyzed. The expressions of TGF-β mRNA and PD-1 mRNA were detected by RT-PCR. Results Compared with control group, Cy-treated mice showed significant decrease in phagocytic percentage(31.86%) and index(0.73±0.06) of macrophage, hemolysin OD value(0.702±0.08), lymphocyte transformation rate(42.22%), spleen index(2.73±0.26), thymus index(1.25±0.21) (P＜0.05). Compared with Cy model group, Sulforaphane increased the number of phagocytic percentage(43.56%) and index(1.15±0.08) of macrophage, hemolysin OD value(1.325±0.10), lymphocyte transformation rate(51.44%), spleen index(3.80±0.46), thymus index(1.89±0.31) (P＜0.05) and down-regulated the expressions of TGF-β mRNA and PD-1 mRNA in a dose-dependent manner. Conclusion Sulforaphane could improve the immune function in immunodepression mice induced by Cy, and inhibit effectively the overexpression of TGF-β mRNA and PD-1 mRNA.