Abstract: Rejection after lung transplantation, including acute rejection (AR) and chronic rejection manifested with chronic lung allograft dysfunction (CLAD), is the main factor affecting the long-term survival of allografts. Exosome, a type of extracellular nanovesicle for intercellular communication among eukaryotic cells, could carry complex biological information and participate in various physiological and pathological processes. Exosome has become a critical immune medium in rejection, regulates the incidence and development of rejection through multiple pathways, and also plays a key role in the monitoring and management of rejection. In this article, the type of rejection after lung transplantation, the mechanism underlying the role of exosome in regulating rejection, exosome acting as biomarkers and the application in rejection treatment were reviewed, aiming to provide a novel direction for comprehensive diagnosis and treatment of rejection following lung transplantation.