Abstract: Pancreas transplantation and pancreas-kidney transplantation are the optimal treatment for renal failure caused by type 1 diabetes mellitus, partial type 2 diabetes mellitus and their complications. Pancreas transplantation mainly includes simultaneous pancreas-kidney transplantation (SPK), pancreas transplantation after kidney transplantation (PAK) and pancreas transplantation alone (PTA). Among all types of pancreas transplantation, biopsy of pancreas allograft remains the best method for definitively diagnosing rejection and differentiate it from other complications. In this article, biopsy methods of pancreas allograft and related research progress, diagnostic criteria and research progress on rejection of pancreas allograft biopsy, and main complications and pathological manifestations of pancreas allograft were illustrated, aiming to provide reference for guiding the clinical diagnosis of the above mentioned complications and ensuring the long-term survival of pancreas allografts and recipients.