The invention provides a constant-temperature constant-
humidity air conditioner. The constant-temperature constant-
humidity air conditioner comprises an indoor unit, an outdoor unit and a
control system, and further comprises a compressor, an outdoor
heat exchanger forming a condenser of the air conditioner, and an indoor
heat exchanger forming an
evaporator of the air conditioner, which are sequentially communicated in a circulating mode, wherein an indoor re-heating
heat exchanger which is in parallel connected with the outdoor heat exchanger is further arranged between the compressor and the indoor heat exchanger; and the indoor re-heating heat exchanger comprises a micro-channel heat exchanger. The indoor re-heating heat exchanger comprises the micro-channel heat exchanger, is relatively small in inside volume and free of influence on
refrigerant circulation quantity while being switched between two
modes of the air conditioner due to low occupied
refrigerant amount, thereby guaranteeing the energy efficiency and the
cooling capacity of the air conditioner. An
electronic expansion valve is arranged behind each of the outdoor heat exchanger and the indoor re-heating heat exchanger; by virtue of control of the double electronic expansion valves, heat quantity of the outdoor heat exchanger and the indoor re-heating heat exchanger is intelligently distributed, thereby precisely controlling indoor refrigerating capacity and achieving a purpose of precisely controlling the indoor environment temperature.