Abstract: Researches on individual thermal adaptation to free-running environment in apartments in Beijing were carried out for 54 occupants, respectively. The individual adaptation characteristics were compared among the 54 occupants from the two aspects: adaptation level to indoor temperature and humidity ratio and the degrees of interaction between indoor temperature and humidity ratio. Then, the differences and similarities of individual thermal adaptation for all the 54 occupants were summarized. Furthermore, cluster analysis was employed to understand group status of thermal adaptation to free running environment of apartments in Beijing. Some typical thermal adaptation patterns were identified and future work was discussed. Finally, the relationship between thermal adaptation levels and occupants’ physiological and psychological features was discussed in detail.