Primary air pressure control method and device

The invention discloses a primary air pressure control method and device. The method comprises the steps that a primary air mother pipe pressure set value is determined according to a maximum coal feeding instruction value; according to the maximum opening value of the hot air adjusting baffle of a coal mill, the maximum opening value of the cold air adjusting baffle and the preset maximum opening value of the adjusting baffle, the pressure set value of the primary air mother pipe is corrected, and the pressure set value of the primary air mother pipe is reduced; and the primary air pressure is adjusted according to the corrected pressure set value of the primary air mother pipe, so that the power consumption rate of a primary fan is reduced. The preset maximum opening value of the adjusting baffle is determined by the maximum coal feeding instruction value. Therefore, the power consumption of a unit plant is reduced and the economical efficiency of the unit is improved under the condition of ensuring safe an