To better characterize the radiation polarization characteristics of the object surface, a two-component polarization bidirectional reflectance distribution function (PBRDF) model based on the Cauchy distribution is established based on the P-G model and the distribution of microfacets on the surface. Based on the transmission characteristics of infrared polarization radiation, a linear polarization model for infrared radiation is derived using the blackbody radiation law. This model is then tested through a designed infrared polarization imaging experiment. Measured data are compared with numerical calculation results to analyze the impact of the Cauchy distribution on the accuracy of the infrared polarization model compared to the Gaussian distribution. The results show that the micro-facet model characterized by the Cauchy distribution is more suitable for describing the infrared polarization degree of an object surface. These findings provide theoretical and technical support for further optimizing the accuracy of the bidirectional reflectance distribution function (BRDF) model.