Abstract: Based on the analysis of the classical Zoom-FFT, a Zoom-FFT algorithm based on Fourier transform spectroscopy was presented. Both FFT and ZoomFFT were used to process the interferogram with different sampling steps by Matlab simulation software, through the comparison of the inverted and original spectrum curves, it indicated that the spectrum could be inverted by both FFT and Zoom-FFT when the sampling step was less than 20 m; But when the sampling step was greater than 20 m and less than 33.3 m, the spectrum could not be inverted by FFT algorithm, while the spectrum could be inverted by Zoom-FFT.