Postmortem interval (PMI) estimation has always been a crucial focus and challenging issue in forensic pathology. In recent years, specific RNA molecules and their variation have been used worldwide to estimate PMI. In this review, we summarize the methods used to detect non-coding RNAs (ncRNAs) for PMI estimation based on the literature, show the existing problems and development trends, and provide technical references for relevant studies and estimation practices. [ABSTRACT FROM AUTHOR]