To study the polarization characteristics about Gaussian rough surface light scattering, the Stokes vector of scattering light is derived based on microfacet theory and polarized bidirectional reflectance distribution function. The polarization characteristics of rough surface scattering light are numerically calculated for both elliptically polarized light incidence and natural light incidence. The effects of incident angle, azimuth angle and complex refractive index on polarization characteristics of scattering light are studied. The result shows that the incident angle, the complex refractive index and the azimuth angle have a great influence on the ellipticity angle and the degree of polarization. The change trends of the degree of polarization curves and the ellipticity angle curves with different incident angles or complex refractive indexes have a high similarity. The change trends of the degree of polarization curves and the ellipticity angle curves with different azimuth angles have a large difference, but the two curves with complementary azimuth angles are symmetric about scattering angle θr=0. The maximum value of the ellipticity angle is obtained around the backscattering direction, and the minimum value of the degree of polarization is obtained in the backscattering direction.