To study the immunoregulatory effect of Streptococcus thermophilus MN-BM-A01 on mice， male kunming mice as animal model， weight and index of immune organs in mice， mice serum IgG and IgM content， sIgA levels in mouse excrement were determined. At the same time， the immunoregulatory effects of MN-BM-A01 was studied by evaluation experiments. Results showed that MN-BM-A01 had no adverse effects on health in mice， the mice spleen changes had a significant impact， in mice thymus changes had little impact； MN-BM-A01 can improve the content of serum IgG， IgM and sIgA levels in mice feces effectively. In the test of evaluate the immune regulation of MN-BM-A01， lymphocyte transformation test of cellular immunity and clearance rate of carbon test of mononuclear macrophage function indexes， in the determination of all have two or more dosage group showed positive. Conclusion： MN-BM-A01 could enhanced the role of immunity in mice.