Infrared polarization imaging technology is a new detection technique, and it can distinguish background and target through the infrared polarization characteristics of target. At the present time, infrared polarization characteristics of targets are always studied by experiments that acquire images including degree and angle of linear polarization. It is known that the infrared polarization information is closely related with many factors, therefore it can be not acquired required data only through polarization image. In order to study infrared polarization imaging theory and infrared polarization characteristics of object closely, infrared polarized emissivity model and control equation for infrared polarized imaging through polarized bidirectional reflectance distribution function are derived, and mathematical expression for polarization information is given, and it is analyzed in theory by considering the influence of effect refractive index and roughness of target surface. This work will provide theory guidance for target detection based on infrared polarization imaging.