Abstract: In order to study moisture content and temperature changes of wood during moisture sorption, adsorption processes of poplar (Populus euramericana Cv.) with size of 20 mm (T)×20 mm (R)×2 mm (L) were investigated from oven-dry state to three different relative humidity conditions of 22%, 47%, and 75% at 30℃. A self-designed temperature chamber was used and thermal images were taken at certain time intervals during the processes. The result showed that: at the beginning of adsorption process, moisture content of the specimens increased significantly, and their average temperatures rose 2-5.5℃ as well. Along with adsorption, the moisture content and average temperature of the specimens were gradually approaching the equilibrium state. The temperature for surface layer along the longitudinal direction of the specimens was higher than that for center layer, and the temperature difference between the surface and center reached the maximum value of 0.8℃ at the first 90 s of the adsorption process and eventually reduced to 0.02℃ at equilibrium state.