To reveal the characteristics of heat and mass transfer in the tobacco packet rewetting process, a heat and mass transfer model of tobacco packet rewetting is established based on multi-physical coupling fields, and the accuracy of the model is verified by the tobacco packet rewetting experiment. The distribution characteristics of the flow, temperature and humidity fields outside the tobacco packet, as well as the heat and mass transfer characteristics inside the tobacco packet have been investigated. The results show that the velocity, temperature and humidity are the highest near the exhaust port. The average increment of water content of the first layer is 3.01%, and the average increment of water content of the second layer is 1.89%. The average increment of temperature of the first layer is 7.84 °C, and the average increment of temperature content of the second layer is 2.47 °C. The moisture content and temperature of the tobacco packet increases the fastest near the exhaust port.