Abstract: Cellular immune system plays a very important role in the body's immune response to malignant tumor. Cytotoxic T lymphocyteassociated antigen 4（CTLA-4） involves in the induction and maintenance of T cell immune tolerance through inhibiting T cell activity，so the monoclonal antibody which blocks the CTLA-4 can stimulate the proliferation of immune cells，thereby enhances the body's immune response to the tumor. This paper mainly reviews the research progresses about CTLA-4 monoclonal antibody drugs（ipilimumab and tremelimumab） in recent years and the clinical application progress of them.