In recent years, CRISPR/ Cas9 technology has become the hottest gene editing technology through its advantages of being flexible, efficient, cheap, and easy to operate, and its ability to edit multiple sites at the same time.The unique CRISPR/ Cas9 RNA-guided mechanism of targeted editing of DNA has not only expanded our understanding of the genetic regulation of organisms, but also demonstrated superior convenience. In the last ten years, CRISPR/ Cas9 has been widely used in various biological and medical research fields and has developed rapidly. Especially in the field of medicine, it has shown great potential. This paper summarizes recent advances in CRISPR/ Cas9 technology, and the mechanism of action and application in medicine of the CRISPR/ Cas9 gene editing system, to provide a reference for the application and optimization of this technology.