Tomatoes (Lycopersicon esculentumMill.) are the principal dietary source of Lycopene which is one of carotenoid and is highly beneficial in preventing some diseases such as the cancer and the heart disease. Suppressing the expression ofLcy gene,the main gene regulating the transformation of the lycopene ,is a convenient and effective way to enhance the content of lycopene. The primers were designed according to the gene sequence(U46919)and (X86452) in GenBank. The fruit-specific promoter—phytoene desaturase gene(Pds) promoter and the DNA segment of the Lcy gene were isolated from the genome DNA of tomatoes. The 3′end ofLcy DNA segment was connected together by an intron to inform the RNA interferential segment then which was inserted in the expression vector with the Pdspromoter to inform the fruit-specific expression vector. The vector was transformed into the tomatoes through theAgrobacterium tumefaciens. Five transformants were obtained. And the PCR proved that the extra_gene was integrated into the tomato genome. The lycopene in the transgenic tomatoes fruit was increased significantly through analysing the contents of lycopene. These results shows that regutating biosynthetic enzyme in carotenoid pathway by RNAi can improve the lycopene content of plant-derived products.