Gene therapy, as a transformative advancement in the biomedical field, has demonstrated great potential in medical research and clinical applications by using gene editing technology and vector delivery means to repair or replace defective genes. In recent years, with the major breakthrough of clustered regularly interspaced short palindromic repeat/CRISPR-associated protein 9(CRISPR-Cas9) technology, the continuous improvement of non-viral vectors and the enhancement of policy support, the application of gene therapy has been expanded from the traditional single-gene genetic diseases to a variety of fields such as oncology, chronic diseases and infectious diseases, showing a wide range of application prospects. Although gene therapy has made significant progress, it still faces many challenges, including safety, efficacy, ethical issues and high treatment costs, which has greatly limited its potential for clinical applications. The aim of this paper is to explore the innovation and development trend of gene therapy technology based on CRISPR-Cas9 technology, to explore the potential of gene therapy in the treatment of genetic diseases, cancer and rare diseases by analyzing the current research progress and clinical applications, and to discuss the direction of the development of this technology in future research, providing a tool for research in related fields.