Taking a central air-conditioning system as an example,this paper presents the influence of indoor design temperature and relative humidity on thermal comfort and energy consumption in an office building in Guangzhou,P.R.China.The study shows that under the identical indoor thermal comfort conditions,the air-conditioning system cooling load increases with the increase of indoor temperature.Increasing the indoor temperature can not decrease energy consumption.In order to reduce the energy consumption in a central air-conditioning system meeting the required indoor thermal comfort condition,an indoor design condition with larger relative humidity and lower temperature is recommended.