Abstract: Due to single intensity modulated polarization spectrum measurement technology has aliasing phenomenon and effective optical path difference is limited, double intensity modulated polarization spectrum measurement was presented. This method not only has the advantage of a single intensity modulation spectropolarimetry, but also effectively eliminates the aliasing phenomenon and improves the effective optical path difference and the spectral resolution by sum-difference processing of the double intensity modulation interference signal. The sum-difference signal Fourier transform was used to get the polarization spectrum. The interference signal of incident spectrum and Fourier inversion spectrum were simulated by MATLAB. Simulation results show that this method effectively eliminates aliasing and gets double effective optical path difference after the sum-difference treatment. The principle for measuring the spectrum of the Stokes components based on the double intensity modulation spectropolarimetry is deduced in detail and its feasibility is proved by the simulation, which provides the necessary theoretical basis for engineering implementation of this method.