Abstract: Type 1 diabetes mellitus is a chronic autoimmune disease caused by the destruction of pancreatic islet β cells. Pancreatic islet transplantation provides a treatment method for patients with type 1 diabetes mellitus to restore endogenous insulin secretion. However, some problems limit the widespread application of islet transplantation, such as shortage of donors and post-transplantation rejection damage. Mesenchymal stem cell-derived exosome (MSC-Exo) have become a potential tool for islet transplantation therapy due to their immunomodulatory and tissue repair capabilities. MSC-Exo shows great promise for application, because of low immunogenicity, easily being store and transported, and the potential as drug delivery vehicles. However, challenges such as preparation, purification, standardization and safety verification need to be overcome before converting MSC-Exo into clinical practice. Therefore, this article reviews the application and potential advantages of MSC-Exo in islet transplantation, aiming to providing more effective and safer treatment options for patients with type 1 diabetes mellitus.