The invention discloses a self-cleaning method for an indoor unit filter screen. The self-cleaning method comprises the following steps that an evaporator is controlled to generate condensed water; anindoor unit fan is controlled to operate in the reverse direction for a predetermined first time, and dust accumulated on the filter screen is blown out into the room; the indoor unit fan is controlled to operate in the forward direction for a predetermined second time, the dust accumulated on the filter screen is sucked into the indoor unit, and the dust accumulated on the filter screen is combined with the condensed water; and condensed water combined with the dust accumulated on the filter screen is discharged. According to the self-cleaning method for the indoor unit filter screen, when amotor rotates normally, the motor rotates forward and backward when the filter screen is cleaned, the fan is driven to blow the dust accumulated on the dust filter screen into the chamber during reverse rotation, the filter screen is cleaned, the fan motor is rapidly changed into forward rotation, and the dust is sucked into the evaporator; and meanwhile, due to the fact that the condensed wateris generated on the evaporator, the dust can be combined with the condensed water, the dust can be discharged to the outside through the evaporator, a water receiving disc and a drain pipe, self-cleaning of the dust filter screen is achieved, the parts do not need to be disassembled, no professional staff is required for cleaning, and convenience is brought to the user for use.