Evaporative cooling is particularly suitable for the region such as dry and hot weather conditions, but in the Non-dry areas, evaporative cooling can not be satisfied with the status of the air supply, which will be combined with dehumidifying technology. Three different dehumidifying air conditioning systems were compared, and a novel air conditioning system was proposed, which compound of evaporative cooling and mechanical cooling dehumidifying, and the energy-saving potential of new system has been analyzed.