The present invention discloses an air-conditioner which can be used for continuous heating and constant temperature dehumidification and has features of improving the indoor amenity in the defrost dehumidification process. The air-conditioner includes compressors, electromagnetic four-way valves, evaporators, throttling devices and condensers connected in sequence to form recycle loops, at leasttwo compressors, electromagnetic four-way valves, evaporators, throttling devices and condensers are respectively provided to form at least two independent recycle loops. By setting at least two independent recycle loops, part of recycle loop adopts heat-production operation in the defrost and dehumidification process, while part of recycle loop adopts refrigeration operation so that it can continuously provide heat in the defrost and dehumidification process, to satisfy the amenity requirement of defrost and dehumidification, and can effectively prevent greater fluctuation of the indoor temperature, especially suitable for promoting in the use of heat pump air conditioning system.