A gas-liquid separator-assisted air conditioner system and its control method, the air conditioner system includes an indoor heat exchanger, an outdoor heat exchanger, a compressor, a four-way reversing valve, two DC frequency conversion fans, two gas-liquid Separator, two one-way valves, three electronic expansion valves, four temperature sensors and control modules; the two heat exchangers of the air conditioner system adopt gas-liquid separation technology, and the Part of the gas-phase refrigerant, and the electronic expansion valve is used to adjust the flow of gas-phase refrigerant, which can effectively reduce the flow resistance loss on the refrigerant side, improve the heat transfer efficiency of the heat exchanger, thereby improving the energy efficiency of the whole machine, and the separation of gas and liquid under condensing conditions When the air conditioner is in the cooling mode, the indoor heat exchanger is used as an evaporator, and the dryness of the refrigerant in the middle of the heat exchanger is already relatively high. At this time, the existence of the gas phase refrigerant will affect the liquid phase refrigerant. evaporation, and increase the flow resistance loss on the refrigerant side; in the heating mode, the outdoor heat exchanger of the air conditioner also has the same problem; the present invention can effectively solve this problem.