The CRISPR/Cas9 genomic editing technique achieves site-specific editing of target genes through the mediation of the wizard RNA and the cleavage of the Cas9 protein. Because of its simplicity and efficiency, it has been widely used in crop genome editing. In the review, we introduced the composition, classification, working principle and g RNA construction method of CRISPR/Cas9 system. The corresponding strategies to solve the off-target effect of the system were also summarized. At the same time, we summa...