After the air conditioner is electrified, the low-pressure steam of refrigerant in the refrigeration system is sucked by the compressor, compressed into high-pressure steam, and then discharged into the condenser. At the same time, the outdoor air sucked by the axial fan flows through the condenser, taking away the heat released by the refrigerant and condensing the high-pressure refrigerant vapor into high-pressure liquid. The high-pressure liquid is injected into the evaporator after passing through the filter and throttling mechanism, and evaporates at the corresponding low pressure to absorb the heat in the indoor air. At the same time, the cross-flow fan makes the air continuously enter the fins of the evaporator for heat exchange, and sends the cooled air indoors after the exchange. In this way, the indoor air continuously circulates and flows to achieve the purpose of cooling down.