Indoor unit of air conditioner and controlling method for indoor air outlet of air conditioner

The invention discloses an indoor unit of an air conditioner. The indoor unit of the air conditioner comprises an air outlet, an air deflector, a controller and a humidity detector; the air deflector is used for shielding or opening the air outlet; and the humidity detector is used for detecting the environmental humidity. When the indoor unit of the air conditioner changes to be a preset operation mode in a refrigerating operation state, the controller can control the air deflector to partially shield the air outlet, and the air outlet direction of air flow can be changed when the air flow passes through the air deflector. After the indoor unit of the air conditioner is in the preset operation mode, the controller can determine whether the air deflector is controlled to open the air outlet according to the environmental humidity detected by the humidity detector to enable the indoor unit to retreat from the preset operation mode. The invention further discloses a controlling method for indoor air outlet of the air conditioner. According to the indoor unit and the controlling method, the phenomenon that condensate water appears on the air deflector is avoided.