A new method of the interferogram formation,recording and processing is proposed for the polarization interference imaging spectrometer. According to the regularities of the optical path difference distribution on the detector, the wide-field-of-view polarization interference imaging spectrometer (WPIIS) is proved to be much suitable for working under temporally and spatially mixed model. In addition, the originally experimental interferogram obtained by WPIIS is processed in this new way, the satisfactory result of interference data and reconstructed spectrum proved that the method is exact and useful.