In order to understand the relationship between the moisture content of tobacco and its microporous structure, and to provide a theoretical basis for the preservation of tobacco, the dehydration rate over 4 000 min of 26 Tobacco samples including flue-cured tobacco, burley tobacco, oriental tobacco, reconstituted tobacco leaf and expanded cut stems were measured (1 time/min) at a temperature of （22±1） ℃ and a relative humidity of 30% using a tobacco dynamic moisture content monitoring device. The α and β values in the thermodynamic Weibull model were calculated from the dehydration rate. Results: At the same storage temperature, humidity and the same time, the rate of water loss of the reconstituted tobacco leaves and the expanded cut stem samples was the highest, followed by the burley tobacco and the oriental tobacco samples, and the flue-cured tobacco samples were the lowest. The values of α and β in the Weibull model of samples were significantly negatively correlated with the average pore diameter of the microwells. The moisture retention properties of tobacco samples were significantly negatively correlated with the average pore diameter of their micropores.