In the remote sensing application, the interferometer, especially Fourier Transform Spectrometer, is required to be of high spectral resolution and high signal to noise (SNR). Therefore, the modulation reduction caused by stray light, which is introduced by multiple reflections of beam splitter and compensator, has been analyzed in detail in this paper. Based on theoretical analysis, the wedge angle and inclination angle are respectively introduced in beam splitter and compensator, which can reduce or even eliminate the influence of stray light by spot separation. The relationships among spot separation angle, wedge angle and inclination angle are given by theoretical formula, which can be used to optimize wedge angle and inclination angle. For the connection of structural parameters, the angle of incidence need to be adjusted with the wedge angle and inclination angle to keep the symmetry of reflected light and transmission light about splitting surface and eliminate the effect on spectral resolution. And then, the thickness of compensator also need to be adjusted, for eliminating the effect of optical path difference changing of regular optical light. The influence of the multiple reflections stray light can be eliminated by following these steps. Therefore, an optimization design method is obtained, which is suitable for the Fourier transform spectrometer using the beam splitter and compensator scheme.