Abstract: Organ shortage is a critical factor limiting the development of organ transplantation. Xenotransplantation is expected to resolve the problem of organ shortage, which has become a new research hotspot. Study of costimulatory signaling pathway related to T cell regulation is a hot topic in terms of immunity of xenotransplantation. Since the discovery of costimulatory molecule CD28, multiple costimulatory molecules have been identified, including costimulatory and coinhibitory receptors and their related ligands. Specific T cell activation of donors is the key factor leading to acute immune rejection. The expression and induction of costimulatory molecules on T cells differ during different immune stages, and these costimulatory molecules play a key role in maintaining T cell tolerance and the balance of T cell immune response. At present, increasing attention has been diverted to the role of costimulatory signaling pathway in organ transplantation. In this article, the latest research progress in costimulatory signaling pathway related to xenotransplantation immunity was reviewed, aiming to provide reference for the optimization of xenotransplantation immunosuppression regimen.