The fan coil unit air conditioning system consists of one or more fan coil units and a cold and heat source supply system. The fan coil unit is composed of fans, coils and filters. As the terminal unit of the air conditioning system, it is installed in each air conditioning room dispersedly, and can independently treat the air. The cold and hot water required for air treatment is prepared by the air conditioning room in a centralized way, and is supplied to each fan coil unit through the water supply system.