To on-linely diagnose faults of train bearings, wayside acoustic signal analysis is one of the most important development directions. However, the Doppler Effect due to relative motion between microphone and acoustic source would cause the acoustic signal spectrum being distorted, which is not beneficial to accurately reflect equipment health conditions. In order to solve the doppler effect of acquisition signal spectrum distortion and accurately restore the original signal spectrum structure, the paper proposes a signal variable sampling method based on frequency shift ratio, which can effectively solve the above problem of distorted spectrum for acoustic signals with the Doppler Effect. Firstly, the curve of frequency shift was figured out with known conditions under measurement; secondly, the frequency shift ratio of every sampling point was obtained based on the frequency shift curve; the last, using variable sampling technology, the new sampling signal was obtained by the interpolation method. The paper improves the resampling method based on frequency shift curve, which has been proposed by the authors previously. The effectiveness of the proposed method is verified by simulation and experiment.