Different from the traditional moving target indicator （MTI） or moving target detection （MTD） algorithms， a clutter suppression method based on triple-spectrum-line interpolation fast Fourier transform （FFT） is proposed. The radar echoes are windowed in the time domain， which is to suppress the spectral leakage and fence effect caused by non-synchronous sampling and periodic truncation. The radar echoes are processed by Fourier transform and triple-spectrum-line interpolated， and the frequency and amplitude components in the same distance unit can be estimated. The estimated results are compared with the clutter velocity threshold， if the estimated results are higher than the threshold， the amplitude value corresponding to the current frequency component is judged to be the target amplitude value， and outputting the Doppler velocity information， otherwise the target is not detected. The feasibility and effectiveness of the method are verified by simulation and experiment.