The hygroscopic characteristic of three types of tobacco leaves from two stalk positions were studied. Tobacco samples were conditioned at constant relative humidity (R.H.) and temperature in a static atmosphere until equilibrium was reached. The moisture content of the tobacco samples was determined by the oven drying method. Experiments were conducted at three different temperatures with ten different R.H.. The isothermal absorption curves of different tobaccos at 20.degree.C, and the same tobacco at three different temperatures, as well as isothermal desorption curves, were compared. It is found that the hygroscopic characteristic of tobacco leaves varies with the type of tobacco, and the hysteresis effect of moisture in tobacco is obvious. The complexity and multiplicate factors in the process of moisture absorption are discussed.