Abstract: for accurately grasping and understanding harvest maturity and explore the role of antioxidant capacity and energy metabolism in postharvest tobacco leaf discoloration, the harvested tobacco leaves were placed in a dark environment. The changes of yellowing, browning, MDA content, conductivity of leaching solution, adenosine triphosphate (ATP) content, adenosine diphosphate (ADP) content, adenosine triphosphate (AMP) content, energy charge (EG) and activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), succinate dehydrogenase (SDH) and cytochrome oxidase (CCO) of samples were determined during the experiment. With the increase of harvest maturity, the yellowing and browning of postharvest tobacco leaves started earlier and developed faster. During the test, the antioxidant enzymes (SOD, POD, CAT) and energy metabolism enzymes (SDH, CCO) were highly active. At the same time, the high-maturity postharvest tobacco leaves had higher MDA content and leachate conductivity in the experiment, and the ATP content peak appeared earlier, and the ATP content and energy charge remained high during the experiment for a shorter period of time. These results indicated that the slower development of yellowing and browning of tobacco leaves after harvest at low maturity may be related to higher antioxidant capacity and energy metabolism.