Compared with ordinary light sources, Gaussian beams have good directivity and have a wide range of applications. COMSOL multiphysics simulation software is used to study the propagation characteristics of Gaussian beams incident at Brewster angle. The simulation results show that under s polarization, the refracted beam is a Gaussian beam, and the direction of the reflected beam is perpendicular to the refracted beam; under p polarization, the refracted beam is a Gaussian beam, and the reflected beam does not exist, but the electric field modulus at the reflection interface shows a double-lobe profile with significantly reduced central intensity and very weak bimodal reflection. Under the different refractive index, the larger the refractive index of the refractive medium, the narrower the intensity concentration range of the refracted beam, the lower the energy, and the smaller the electric field modulus difference between the refracted beam and the incident beam.