Polarization integrated detector has the advantages of small size, light weight, compact structure, and no need for image registration to detect and recognize the dynamic targets simultaneously at the same place. This article mainly introduces the research progress and applications of polarization integrated infrared detector. We analyse the key technologies for obtaining high extinction ratio polarization integrated detectors, such as grating structure design and simulation, submicron polarization grating preparation, integration and testing, polarization image data reconstruction, etc. Finally, we introduce the typical applications of polarization imaging in unmanned aerial vehicles, camouflaged trucks, landmines, sea vessels, facial recognition, road recognition, sea oil leakage detection, medical detection, etc.