In this work, after analyzing the noise characteristics of interferograms from a spaceborne Fourier transform infrared spectrometer, a method for suppressing impulse noise is proposed. After calculating the symmetrical points and the sampling points on both sides of the interferogram obtained by the sampling points and the relative zero optical path difference, the reference values for the interpolation points obtained are established. The impulse noise position is then determined by comparing a threshold with this reference value. Experimental results show that the relative spectral deviation of the proposed method can be suppressed from 0.24% to 0.17%; furthermore, the noise equivalent radiance difference is suppressed from 0.069 to 0.056 mW·m ^-2·sr ^-1·cm. The proposed method can suppress the impulse noise while retaining the effective spectral information, thereby improving the detection sensitivity of the spaceborne Fourier transform infrared spectrometer.