Abstract: Gene editing is a new technology that can modifies targeted genes.The new gene editing technology (CRISPR/Cas)is made up of clustered regularly interspaced short alindromic repeats(CRISPR)and associated proteins (CRISPR associated,Cas).One editing system which consists of protein Cas9 and CRSPR is widely used in plant genome editing due to its easy operation.Hence,it embodies huge potential.This review introduced the function principle,deve-lopment process of CRISPR/Cas9 system,and its effect of site-specific modification in plant genome.The application of CRISPR/Cas9 in crop breeding,especially in rice,wheat and maize was analyzed,and the results showed that its effects in improving traits related to yield and quality of rice,powdery mildew resistance of wheat and ethylene sensitivity of maize.In the future study,the researchers should design the corresponding operation schemes according to the breeding goal and in-depth understanding of functions of the target genes;improve the system efficiency towards target genes,strengthen the system security to promote the application of gene editing in crop breeding and accelerate breeding process.