The equilibrium absorption content was measured in different conditions by static method.The relations between the pyrolysis temperature,the size of bamboo charcoal particle,absorption temperature and the surface area were studied.The results showed that two kind of bamboo charcoal whose pyrolysis temperature were 700 ℃ and 1000 ℃ had the best absorbing ability.The size of bamboo charcoal particle had little influence on absorption.The ability of absorption could be decreased as the environmental temperature increased.The phenomena of moisture absorption hysteresis were found during moisture desorption and absorption.