The present application discloses an air conditioning system and a control method therefore. An intermediate heat exchanger can include a first heat exchange portion and a second heat exchange portion, a first end of the first heat exchange portion is in communication with an inlet of a compressor, a second end of the first heat exchange portion is communicable with an outlet of a second heat exchanger and/or a second end of the first heat exchanger, a first end of the second heat exchange portion is communicable with a first end of the first heat exchanger, and a second end of the second heat exchange portion is communicable with an inlet of the second heat exchanger and/or an outlet of the compressor. In the refrigeration mode, the first branch can have an adjustable amount of flow. Performance of the air conditioning system can be enhanced.