Postmortem interval (PMI) estimation has always been an important and difficult issue in the field of forensic pathology. In recent years, research progress on the estimation of PMI using RNA specific variation patterns after death has been made by researchers at home and aboard. This paper summarizes the specific application methods of messenger RNA and non-coding RNA for PMI estimation based on the literatures and discusses the existing problems and development trends, in order to provide technical reference for related studies and estimation practic