Abstract: In order to investigate the effects of varous maturity on indexes of quality and security for flue-cured tobacco leaves, the different indexes of chemical components that were related to quality and security of the flue-cured tobacco leaves with different maturity under a consistent growing condition were researched by taking cultivar G80 as trial materials. The results demonstrated that the quality and usability of unripe tobacco leaves were lower than those of mellow leaves. The contents of carbonaceous compounds, such as soluble saccharide, petroleum ether extract and volatile acid in mellow leaves were higher than in overripe leaves, but nitrous compounds, such as nicotine, total nitrogen, volatile alkali, in mellow leaves were lower than in overripe leaves. Although the contents of tar in overripe leaves were remarkably low, the release amount of polynuclear aromatic hydrocarbon was as much as that in mellow leaves. It is better to control maturity in a mellow range to produce and purchase flue-cured tobacco leaves because the cigarette market is mostly one of Chinese style flue-cured tobacco type.