Abstract: With the rapid development of nanotechnology, the research and development of nanomedicines have become one of the development directions of drug innovation. Nanomedicines have special physical and chemical properties, such as nanoscale effects and nanostructure effects, so they have special biological properties, which may change the pharmacokinetic profiles such as absorption and tissue distribution of drug molecules, and thus affect their safety and effectiveness. There are many special concerns on the non-clinical safety evaluation of nanomedicines at the basis of ordinary drug because of the particularity of nanomedicines. On August 25, 2021, China issued Guidance on Non-clinical Safety Evaluation for Nanomedicines(interim). This article interprets comprehensively the guidance, focuses on the key points of non-clinical safety evaluation for nanomedicines, and expounds combined with some cases, aiming to provide reference for drug researchers.