The invention relates to construction of rice transgenic materials and aims to provide a 
gene editing method for knocking out rice MIRNA393b stem-loop sequences with application of a 
CRISPR(clustered regulatory interspersed short palindromic repeat)-Cas9 
system. The 
gene editing method comprises steps as follows: gRNA target sites are selected for 
cloning and GG linking, 
enzyme digestion is performed after amplification, and a product is linked with a pGREB 32 vector; 
escherichia coli competent cells are transformed; plasmids with a correct sequencing result are used for transforming agrobacteria, transgenic plants are obtained through mediated transformation of rice calli, and transgenic positive lines are obtained; the T0-generation 
mutant plant seeds are collected for seeding, and the T1-generation plants are subjected to homozygote screening; homozygous lines which are discovered to be negative through MIRNA393b expression are rice mutants completely losing the MIRNA393b stem-loop sequences and MIRNA393b stem-loop sequence expression. According to the 
gene editing method, MIRNA stem-loop sequences can be effectively knocked out, and loss-of-function mutants of different members in the same MIRNA family can be prepared; the 
mutant plant propagates to obtain a large number of seeds and is an ideal material for acquiring rice MIRNA393b gene functions successfully.