Abstract: To study habitat selection by eastern hoolock gibbons (Hoolock leuconedys), a family consisting of an adult male, an adult female and a subadult, and a solitary female were tracked from March 24 to May 6, 2006 and from October 19 to November 29, 2006 at Gaoligong Mountain (25°49′44″N, 98°46′07″E) in western Yunnan Province, China. Thirty used sites and 30 corresponding available sites were established separately in the spring and autumn and 24 factors in these sites were measured and analyzed to characterize differences between habitats selected by the eastern hoolock gibbons in spring and autumn. The gibbons favored areas between the middle and bottom of eastern slopes to avoid cold westerly prevailing wind and preferred regions dominated by Quercus variabil and Eurya pseudocerasifera trees in the spring and preferred regions dominated by Lithocarpus truncatus and L. leucostachyus trees in the autumn. Dense bamboo forests and dense liana were important for food and security and for providing fast routes to reach arbors, respectively. In spring 12 factors among the 16 quantitative factors significantly affected habitat selection while altitude, distance to open field, average height of shrubs and shrub density did not affect habitat selection. In autumn distance to road, distance to Amomum tsaoko plantations, shrub density, bamboo density, average height of bamboo and liana density significantly affected habitat selection. In autumn, Amomum tsaoko harvesting forced the gibbons to skirt open field of Amomum tsaoko plantations and migrated through steeper ravines and creeks by using rattans to move up and down.