In order to acquire spectral polarization information of the image under single-frame imaging conditions, an encoding aperture measurement method based on intensity modulation was proposed. The method used the spectral polarization intensity modulation module composed of an achromatic 1/4 wave plate, a multistage phase retarder and an analyzer, and modulated the spectrum of each element of the Stokes parameters of the incident light to different frequencies. And the modulated spectrum was compressed and coded by a spectral imaging system composed of coded aperture and dispersive prism, and was detected by CCD. The modulated spectral information was reconstructed using the TwIST algorithm, and then the spectrum of Stokes elements can be reconstructed by further separating the spectrum channels. Taking a single pixel as an example, the modulation of incident light intensity modulation, spectral reconstruction, and demodulation of Stokes parameters were simulated numerically. The results show that this method can achieve the acquisition of spectral polarization information of sparse images. This process requires only one measurement of the image and therefore has a high-speed acquisition capability.