Air conditioning system, control method and device thereof and storage medium

The invention provides an air conditioning system, a control method and device of the air conditioning system and a storage medium. According to the air conditioning system, a first conveying pipe of a gas-liquid separator communicates with the second end of an indoor heat exchanger, and a second conveying pipe of the gas-liquid separator communicates with the first end of an outdoor heat exchanger; a third conveying pipe of the gas-liquid separator is connected to a gas return pipeline between the four-way valve and the compressor and is communicated with the gas return pipeline; or the third conveying pipe of the gas-liquid separator is connected to the medium-pressure cavity of the compressor; and the gas-liquid separator is used for carrying out gas-liquid separation on the refrigerant from the first conveying pipe or the second conveying pipe, and the separated gaseous refrigerant is output from the third conveying pipe. The refrigerant from the indoor heat exchanger or the outdoor heat exchanger is well subjected to gas-liquid separation, the gaseous refrigerant is not input into the outdoor heat exchanger, and the utilization rate, the heat exchange performance and the energy efficiency of the heat exchange area of the outdoor heat exchanger are improved.