Abstract：Objective：To study the anti-sepsis effect of Marsdenia Tenacissima(Roxb) Moon(DBJ)，a national medicine， and to reveal its anti sepsis immunological mechanism. Methods： The sepsis model was established by intraperitoneal injection of bacterial lipopolysaccharide. It was randomly divided into normal control group， model group and DBJ alcohol extract 100 mg/kg and DBJ alcohol extract 200 mg/kg groups. The survival rate was counted after 24 and 48 hours of drug intervention.HE staining was used to detect the degree of pathological injury of lung and liver. The proportion of lymphocyte subsets(CD3+ T cells，CD4+ T cells，CD8+ T cells，TCR+ T cells and B cells) was detected by flow cytometry.The expression of T cell subsets(Th1，Th17 and Treg) was measured by flow cytometry. Results：Compared with sepsis model group，DBJ alcohol extract improved the survival rate of sepsis model mice，reduced the infiltration of inflammatory cells into lung and liver tissue， and had a better protective effect on lung and liver pathological injury. DBJ alcohol extract decreased the expression of B220+ B lymphocytes(P＜0.05)，but had no significant effect on the proportion of CD3+ T cells，CD4+ T cells， CD8 + T cells and TCR + T cells in sepsis model mice(P＞0.05)，and significantly increased the proportion of CD4 + Foxp3 + Treg cells(P＜0.05)，but had no effect on the expression of Th1 cells(CD4+ IFN-+ T cells) and Th17 cells(CD4+ IL-17A+ T cells)(P＞ 0.05). Conclusion：DBJ has a significant therapeutic effect on sepsis，and its mechanism may be related to the induction of regulatory T cells and the mediation of immune homeostasis and tolerance.