Abstract: To gain the desirable activity of biomolecules, directed evolution is served as a competent technology depending on high quality mutant library, effective selection and screening, which has been widely used in food, industry and medical fields. CRISPR (clustered regularly interspaced short palindromic repeats) has developed rapidly in recent years, and various CRISPR derivatives have been developed to meet directed evolution, allowing people to evolve specific genes in situ in a wide range of hosts. At the same time, the way of generating genetic diversity through artificial or natural pathways has given people more choices, and more efficient evolution strategies can be adopted according to research needs. This article will first introduce the CRISPR tools, then summarize the CRISPR-mediated mutation and screening platforms and finally discuss the development trends and opportunities of the CRISPR in the field of directed evolution.