Polarization imaging is a novel photo detection method. Compared with traditional intensity imaging, polarization imaging can further obtain the polarization characteristics of the target, therefore improving the contrast and increasing the recognition probability. Polarization imaging has important application value in biomedical, industrial inspection, earth remote sensing, modern military, marine and aviation fields. The imaging methods of polarization imaging systems are classified and compared, and the realization methods of polarization imaging are summarized. On this basis, according to the characteristics of different polarization imaging systems and different application backgrounds, the future development direction of polarization imaging systems is prospected, including new polarization imaging systems based on metasurfaces and new polarization imaging spectroscopy systems.