The microfacet bidirectional reflectance distribution function (BRDF) model with the two-parameter Cauchy probability distribution,which substitutes for the model with general Gaussian distribution,is used. The directional dependence of emissivity of the object is also taken into account. On the basis,the deduction of mathematical model of long-wave infrared (LWIR) polarization is described. Reasonable simplification and correction for the model is made in order to make the model to be suitable for simulation. Then this paper analyses how to choose the two parameters (σ and q) of the mathematical model and gives the flexibility validation and advantages of the model. The whole process of simulation is done by using C language,the flow of which includes modeling,processing and importing the file into the system of simulation,setting the parameters of polarimetric model,computing the radiation transfer and rendering surface using Gouraud algorithm. The result of polarimetric scene simulation is desirable,which is basically in conformity with real imagers. It proves that the mathematical model and the algorithm in this paper are adequate for the research of LWIR polarization. The conclusion of this paper is significant basis for studying the LWIR polarimetric characteristic of complex objects.