Abstract: With the improvement of people’s living standards, the demand for aquatic products is also increasing. Fish farming is an important part of aquaculture. How to increase the output of fish farming has become a problem to be solved. Breeding has made a significant contribution to improving the yield of farmed fish. To meet the growing global demand for high-quality protein, there is an urgent need to apply new technologies to accelerate the breeding process to further improve fish yield. Gene editing technologies, including ZFNs, TALLENS, and CRISPR/Cas9, are current tools for accelerating genetic improvement. Among them, CRISPR/Cas9 technology has the advantages of fast speed, low cost, and high precision in editing genes, so its application in gene editing in fish farming is rapidly emerging. At present, it has been applied to more than 20 fish culture varieties for improving superior traits. This review summarized CRISPR/Cas9 technology and its application in fish aquaculture, current status and future development direction, in order to provide some reference for the application of CRISPR/Cas9 technology in fish aquaculture.