Abstract: Myeloid-derived suppressor cell (MDSC) is a type of heterogeneous cell derived from bone marrow, which was first found in tumor. MDSC can inhibit the function of T cell with immunosuppressive effect. In recent years, more and more studies have shown that in the field of organ transplantation, MDSC can also regulate the host's immune function, induce specific immune tolerance, and play a protective role in transplant organs, which is expected to become a new target in clinical treatment of transplant rejection. The biological characteristics of MDSC and the mechanism of immune tolerance induced by MDSC were reviewed in this paper.