The invention relates to a reactor vibration signal acquisition system and a vibration signal characteristic frequency extraction method. The vibration signals of the reactor are collected through vibration sensors arranged on the periphery of an iron core, a winding and the oil tank of the reactor, and the vibration signal characteristic frequency is extracted through fast Fourier transform. Thereactor vibration signal acquisition system provided by the invention can quickly and accurately acquire the vibration signal of the reactor, and provides a reliable theoretical basis for later faultdiagnosis based on the vibration signal; and the reactor vibration signal characteristic frequency extraction method provided by the invention adopts a fast Fourier transform method, so that the calculation amount is reduced, and the reactor signal characteristic frequency can be extracted more quickly.