Data on activity patterns and time budgets were collected from one Thesus Macaques (Macaca mulatta) in Nonggang Nature Reserve via instantaneous scan sampling to explore their behavioral adaptation to the Karst habitat from September 2006 to August 2007. Our results indicated: the diurnal activity pattern of rhesus macaques showed morning and afternoon feeding peaks, with a midday resting peak, which represents an adaptation to the changes of diurnal temperature and sunlight.Macaques spent ca.37.3% of their daytime feeding, 29.6% resting, 25.2% moving, 5.5% playing, 2.2% grooming, and 0.2% for other behaviors.Their time budgets varied seasonally: the macaques spent more time playing in the rainy season than in the dry season.There was significant and positive correlation between the monthly percentages of time spent on playing and the monthly proportion of fruits in the diet.They also differed among different sex classes: adult males spent more time moving, whereas adult females devoted more time to grooming.