A polarization imaging spectrometer based on a modified Savart polariscope with a moving wedge prism is presented. The principle of the instrument is described, and the optical path difference as a function of the moving wedge prism's moving displacement is calculated and analyzed. It employs a common-path configuration and is not sensitive to the nonuniform variation of moving speed and environmental vibrations. In comparison with the polarization imaging spectrometer based on the Savart polariscope, this spectrometer is a framing instrument rather than a pushbrooming device. Only the transmission of birefringent materials and detector sensitivity limit the available spectral range of such an instrument.