Abstract: The equilibrium moisture content of redrying lamina of flue-cured tobacco grown in Yunnan province was determined with the conditioning box method. Each test circle was completed in 2~3 days. It was founded that the equilibrium moisture content of tobacco Samples was increased with the rise of environmental humidity at a certain temperature and the changes of the equilibrium moisture content with the temperature was quite different under the different range of the environmental humidity. The changes of the equilibrium moisture rate at the certain environment temperature and humidity were compared and the moisture absorbing process of tobacco was also discussed.