We collected data on diet activity rhythm and time budget from one large group of wild rhesus macaques（Macaca mulatta）in Nonggang National Nature Reserve between September 2007 and August 2008. Instantaneous scan sampling was used for data collection. We examined the influences of environmental and social factors on the activity rhythm and time budgets, and assessed behavioral strategies in karst habitat. Our results indicate that macaques showed morning and afternoon feeding peaks, with a midday resting peak, possibly as an adaptation to temperature and sunlight. During the study period, macaques spent an average of 15.1% of their daytime feeding, 42.1% resting, 34.5% moving, 2.0% playing, 5.2% grooming, and 1.3% other behaviors. Additional, macaques adjusted their activity budgets in response to the changes in diet composition, spending more time moving when they increased fruit consumption. The percentage of time devoted to different activities differed significantly among different sex-age classes. Adult males spent more time resting, whereas adult females spent more time feeding and grooming. Immature individuals spent more time playing. Compared to a sympatric small macaque group, our study group spent more time resting, and less time feeding, which could be related to crop-raiding by our study group.