The invention provides an air conditioner. The air conditioner comprises a compressor, a four-way valve, an indoor heat exchanger, a throttling device, an outdoor heat exchanger, a defrosting bypass branch and an intermediate heat exchanger, wherein the compressor, the four-way valve, the indoor heat exchanger, the throttling device and the outdoor heat exchanger are connected to one another to form a main loop; gas exhausted from the compressor enters the outdoor heat exchanger through the defrosting bypass branch so that defrosting can be implemented; the intermediate heat exchanger comprises a first branch and a second branch, and is serially connected between the outdoor heat exchanger and an indoor heat exchanger through the first branch; the second branch is connected to a defrosting liquid outlet of the outdoor heat exchanger and a gas sucking opening of the compressor; and defrosting refrigerant, refrigerant in the second branch and refrigerant in the first branch are in heat exchange, and enter a gas sucking opening of the compressor after being evaporated. By-pass defrosting can be implemented by the gas exhausted from the compressor, by the intermediate heat exchanger, the evaporation efficiency of the refrigerant is improved, the defrosting speed is increased, and the thermal comfort of a room and the heating energy efficiency of the air conditioner are improved. The invention also provides a control method of the air conditioner.