The invention belongs to the technical field of new energy power generation of a power system, and particularly relates to a power disturbance value response-based frequency modulation control method of a draught fan. The frequency modulation control method comprises the following steps of 1, performing load-reduction running of a wind power plant, and providing frequency modulation rotation reserve for a power grid; 2, monitoring a power balance and standby state of the power grid and the power wind plant in real time when the wind power plant normally runs; 3, judging whether a frequency modulation measure of the wind power plant is triggered or not when a power of the power grid abruptly changes; 4, selecting the wind power plant participating in frequency modulation according to electrical distance between the wind power plant and a disturbance node; 5, calculating emergency power support capacity of the wind power plant; and 6, performing emergency power control. By the frequency modulation control method of the draught fan, the transient frequency deviation amplitude and the frequency recovery time after disturbance of the system can be reduced; and meanwhile, compared with traditional droop control of the draught fan, the frequency modulation control method has the advantages of higher controllability and rapidness, and a technical support is provided for improving wind power absorption capability.