The invention discloses a fireproof controlling method for a variable-frequency air conditioner. The method comprises the following steps: in an operation process of the air conditioner, acquiring temperature inside a power plug of an air conditioner in real time as current power supply temperature, and acquiring the temperature of the air conditioner in the room as current indoor environment temperature; acquiring temperature difference between the current power supply temperature and the current indoor environment temperature as current temperature difference, and comparing the current temperature difference with set threshold; controlling the air conditioner to stop when the current temperature difference is more than first set threshold; and adjusting the working current of a compressor of the air conditioner and a blower of the air conditioner when the current temperature difference is less than the first set threshold and not less than second set threshold to ensure that the first temperature difference is less than the first set threshold. By applying the fireproof controlling method disclosed by the invention, the accuracy and the reliability of fireproof control are improved based on temperature adjustment comfortability of the air conditioner.