The polarization Bidirectional Reflectance Distribution Function (p-BRDF) can describe the spatial polarization characteristics of the reflected light on an object’s surface, and has been widely used in many fields.Based on the microfacet theory, the electric field vectors of polarized incident and reflected light are decomposed and composed by the angle relationship between the microfacet and the object surface, as well as the Fresnel reflection on the microfacet, to obtain the polarization reflectivity.This is then used as the Fresnel reflection term in the Cook-Torrance BRDF model to establish a polarization microfacet BRDF model.Introducing polarization into geometric optical model is simple and has clear physical meaning.The Particle swarm optimization algorithm is used to fit the parameters in the model with the in-plane BRDF experimental data on the brass surface.The standard mean squared error of the model parameter selection is between 0.2820% and 5.7049%, and the best adjusted R² is 0.9957.The results indicate the feasibility of using the polarization microfacet BRDF model to describe the polarization reflection characteristics.