PURPOSE: To provide a method for controlling humidity of an air conditioner in which excessive humidifying is prevented by considering absolute humidities of supplied air and circulated air.

CONSTITUTION: A method for controlling humidity of an air conditioner has a temperature/humidity controller 4 for connecting the air conditioner 1 having a cooler/heater 2, and a humidifier 3 to a living room 7 through a supply air duct 6 and a circulation air duct 9 to control the cooler/heater 2 and the humidifier 3. The method comprises the steps of previously storing set values of a supply air temperature Ts and a circulation air relative humidity Hr in the controller 4, sensing the temperature Ts, the humidity Hr and a circulation air temperature Tr, calculating a supply air absolute humidity Xs from the temperature Ts and the supply air relative humidity Hs, calculating a supply air absolute humidity set value Xsset from the temperature Tr, and closing a humidifying amount control valve 3a of the humidifier 3 when the humidity Xs exceeds the value Xsset.