Abstract: With the development of organ transplantation in clinical practice, allograft pathology has been constantly developing and advancing. The convening of Banff conference on allograft pathology and the establishment of Banff classification on allograft pathology (Banff classification) are pivotal milestones in the development of international allograft pathology. Since then, Banff classification on pathological diagnosis of various transplant organs have been continually updated and improved. Ultrastructural pathological observation by electron microscope plays an irreplaceable role in the early diagnosis of antibody-mediated rejection, recurrent disease and de novo disease of renal allograft. Early detection and rational treatment help to maintain the long-term survival of renal allograft and reduce the failure of renal allograft. In this article, the basic definition of electron microscope and the ultrastructural pathological diagnosis, the research history and main progress on electron microscope diagnosis on Banff classification for renal allograft pathology were introduced, and typical pathological changes, specific terminology and diagnostic criteria of electron microscope diagnosis on renal allograft biopsy were summarized, aiming to provide reference for clinical and basic research of organ transplantation.