The invention relates to a constant temperature dehumidification control method of an air conditioner. The method includes a compressor, a condenser, an outdoor fan, an
evaporator, an indoor fan and an auxiliary electric heater. The method comprises the steps of A, enabling the air conditioner to enter a constant temperature dehumidification
operation mode, starting the compressor and the auxiliary electric heater, and operating
air conditioning system by a refrigerating circulating manner; B, detecting the indoor
environmental humidity psi 1 through the air conditioner, and determining the difference to the set
humidity psi 2; if the difference is not less than psi, entering step C; if the difference is less than psi, entering step D; C, controlling the indoor fan to rotate at medium rotating speed V, and keeping the auxiliary electric heater and the compressor running; D, controlling the indoor fan to run at a low rotating speed V1, and keeping the auxiliary electric heater and the compressor running; E, stopping the compressor when the indoor
environmental temperature psi 1 is reduced to reach the set temperature psi 2, and controlling the indoor fan and the auxiliary electric heater to continuously run for a period of time T, and then stopping the air conditioner. The control method is simple; indoor constant temperature can be ensured while dehumidifying; in addition, the dehumidifying capacity can be increased, the
power consumption of the air conditioner in dehumidifying can be decreased, and as a result, the operation efficiency of the air conditioner can be improved.