The invention provides a fan control method and device. The method comprises the steps: obtaining on-off state information of smoke exhausting equipment arranged at a plurality of floor air inlets in a flue and the equipment information of the smoke exhausting equipment; when the smoke exhausting equipment in an on state exists, determining target air pressure and target air volume of smoke exhausted from the flue according to the equipment information of the smoke exhausting equipment in the on state; according to the target air pressure and the target air volume, determining the target frequency of a fan arranged at a flue outlet by using a preset air pressure and air volume curve; sending a control signal to a frequency converter, thus enabling the frequency converter to drive the fan to work according to the target frequency, and then exhausting the smoke exhausted by the smoke exhausting equipment in the flue. The method achieves the technical effects that the working frequency of the fan is adjusted along with the change of the air volume and the air pressure in the flue, and the demand of the air pressure and the air volume is matched with output; energy is saved, and the smoke exhausting effect is good.