Infrared polarization imaging can use the difference of objects in the degree of polarization to detect the targets against the complex background. In the battlefield, because the man-made and natural objects have a difference in the degree of polarization, the use of infrared polarization imaging can improve one's ability to distinguish the camouflage from the nature. Firstly, the theory of polarization imaging and its system components are presented. Then, the target feature extraction based on the polarization image processing is analyzed. The polarization image quality evaluation, image fusion, image segmentation and feature extraction methods are studied. Finally, the applications based on infrared polarization imaging at abroad are given and the value of this technology to military applications is pointed out.