In this study,tobacco leaves (cultivar NC89) were transformed by the Agrobacterium-mediated with a dual-target FAD2 and FatB genes silencing RNAi vector,which was successfully constructed by our previous study.Further,transgenic plants were screened and fatty acids in seeds were analyzed.The results have shown that the expression levels of FAD2 and FatB in seeds of transgenic plants were decreased by 23% and 11% compared with the control group.The contents of saturated fatty acid,palmitic acid and stearic acid,reached to 8.02% and 4.45% in the fatty acid composition of transgenic seeds,respectively.The content of polyunsaturated linoleic fatty acid was 76.82%.Compared with the control group,the contents were reduced by 2.91%,9.92% and 3.47%,respectively.The content of monounsaturated fatty acid oleic acid in transgenic plants reached to 7.48%,which increased by 46.38% than the control.The results have shown that simultaneous inhibition of FAD2 and FatB expression levels in tobacco seeds significantly increased the content of oleic acid composition,which laid a foundation for the further improvement of oil crop quality.