Fuente: WIPO "tobacco agriculture" The invention discloses a synthetic gene as well as a method and application for establishing a tobacco multi-gene site-directed mutation vector. A sequence of the synthetic gene is one or multiple gene repeated sequence synthesized in a nucleotide sequence of tRNA+sgRNA+gRNA. The synthesized gene is connected into a pUC57-Kan escherichia coli clone antibody. The synthetic gene sequence is obtained by augmentation in two ways. The established vector is used for transforming the tobacco, and a transgenic tobacco plant with the multi-gene being successively knocked out is selected by virtue of sequencing. The synthetic gene is suitable for simultaneously causing the site-directed mutation and application of multiple target genes in one transgenic tobacco, so that a rapid and simple method isprovided for researching the interaction of multiple genes in the tobacco.