Abstract: In order to investigate the effect of removing chemical components on moisture sorption and hygroexpansive behavior of wood, Cunninghamia lancolata Hook specimens, with the size of 20 mm(T)×20 mm (R)×4 mm(L) were divided into three groups as untreated, extractives removed, and delignificated. The samples were exposed to successive adsorption in three relative humidity conditions of 45%, 60% and 75% at 25℃, and moisture and dimensional changes in radial and tangential directions were measured during the processes. The results showed that: moisture and dimensional changes of all the three groups increased rapidly at the initial stage during adsorption and the adsorption rate gradually decreased as the sorption proceeded until equilibrium state was reached. Among the three groups, the delignificated samples exhibited the highest hygroscopicity, followed by the extractives removed samples and untreated wood. After removal of extractives, Cunninghamia lancolata specimens showed a slight increase in both radial and tangential dimensional changes, which did not affect transverse anisotropy much; whereas, radial and tangential dimensional changes of the delignificated samples increased considerably with an obvious reduction in transverse anisotropy. In addition, moisture content of the samples was linearly related to dimensional changes during the continuous adsorption processes as well as at equilibrium state. Furthermore, the delignificated samples had the greatest value of moisture sorption coefficient and humidity expansion coefficient, followed by the extractives removed samples and untreated wood.