Abstract: Rejection is the main cause of transplantation failure. Currently, the specificity and sensitivity of clinical parameters are relatively poor, which cannot accurately prompt the exact cause of rejection. It is of great clinical significance to explore novel biomarkers for monitoring the rejection. In this article, the latest research progress on the biomarkers of rejection risk in organ transplantation were summarized from the perspectives of transplantation pathology, immune cells and regulatory immune cells, non-human leukocyte antigen antibodies, exosomes, cell-free DNA and combination gene prediction, aiming to provide reference for early warning and treatment of rejection in organ transplantation.