The invention provides an air conditioning system capable of controlling supply air humidity and a control method of the air conditioning system, and relates to the technical field of air conditioningsystems. The air conditioning system structurally comprises a compressor refrigerating and dehumidifying system, a humidifying system, a controller, an outdoor fan, an outdoor environment temperaturesensor, an air conditioning return air temperature sensor, an air conditioning return air humidity sensor, an indoor fan and an air conditioning supply air temperature sensor, wherein the compressorrefrigerating and dehumidifying system comprises a compressor, a condenser, a primary throttling valve, a primary evaporator, a secondary throttling valve and a secondary evaporator which are connected successively; the compressor refrigerating and dehumidifying system further comprises a by-pass valve; the by-pass valve is in parallel connection with a primary throttling device; the humidifying system comprises a humidifier; and the compressor, the outdoor fan, the outdoor environment temperature sensor, the air conditioning return air temperature sensor, the air conditioning return air humidity sensor, the indoor fan, the air conditioning supply air temperature sensor, the humidifier, the primary throttling valve, the secondary throttling valve and the by-pass valve are separately connected with the controller electrically, and are controlled by the controller.