The invention discloses an air conditioner indoor / outdoor unit cleaning method. The method comprises the steps of: controlling a
heat exchanger to be cleaned to enter a self-cleaning mode; adjusting the operation frequency of an air conditioner, the openness of a throttling device and the rotating speed of a fan corresponding to the
heat exchanger to be cleaned, and controlling the
evaporation temperature of the
heat exchanger to be cleaned to keep in a preset range to condense the surface of the heat exchanger to be cleaned; condensing the heat exchanger to be cleaned by t1 time; detecting if the high / low
pressure difference of the air conditioner reaches preset conditions; controlling a four-way valve to change the direction to perform the
defrosting switching of indoor and outdoor heat exchangers when the high / low
pressure difference of the air conditioner reaches the preset conditions; and adjusting air conditioner operation parameters when the high / low
pressure difference of the air conditioner
dose not reach the preset conditions, and then, controlling the four-way valve to change the direction to perform the
defrosting switching of the indoor and outdoor heat exchangers when the high / low pressure difference of the air conditioner reaches the preset conditions. As the direction change of the four-way valve can be controlled through detecting if the high / low pressure difference of the air conditioner reaches the preset conditions, the higher shock on the compressor caused by excessive high / low pressure difference of the air conditioner can be prevented.