Abstract: A denoising method for interferogram was proposed based on the improved spin filtering by analyzing the production and characteristics of the interferogram of spatial heterodyne spectrometer. Filtering was carried out on tangent fringe-pattern to reduce the influences of random and dark spot noises without changing the details of fringe-pattern. In addition, the background noise of average spectrum was effectively decreased, the ratio of characteristic spectrum to background noise was increased. Results show that by using the spin filter method, the SNR of the average spectrum of interferogram is improved by 47% without noise and 240% with noise, respectively, and the characteristic spectra with small peak values can be extracted from the background noise to improve the recognition rate of spatial heterodyne spectroscopy as far as weak characteristic spectrum is concerned.