Aiming at the moving mirror tilt in the Michelson interferometer, the influence factors of interference modulation degree under the rectangular and circular clear apertures are analyzed by the interference theory. Simulation results show that the interference modulation degree is related with the clear aperture r,wavenumber v?, and tilt angle θ. In order to ensure the performance of the interferometer, the degree of interference modulation should not be less than 90%. When the wavelength is λ, the tilt angle θmax of the moving mirror for the rectangular and circular apertures should be less than or equal to λ/(16r) and λ/(14r), respectively. Within the control range of the tilt angle of the moving mirror, Matlab is used to simulate the influence of monochromatic light on the sinusoidal tilt error and random tilt error. The results show that the tilt angle of the moving mirror should be controlled at about 1″, which has certain reference value for the structural design and development of the spectrometer.