A light source module for generating polarized light includes a light emitting element, a reflector, and an optical element. The light emitting element generates a light ray, and the reflector reflects the light ray towards the optical element. The optical element includes a light splitting face and a reflection face. The light splitting face receives the light ray, and an angle between the light splitting face and the incident light ray is at about a Brewster's Angle. After the light ray is irradiated to the light splitting face, the light ray is divided into a refraction light and a reflection light. The reflection face reflects the refraction light, and the reflection face is substantially perpendicular to a path of the refraction light. Therefore, a light source with a high degree of polarization is realized by a design of the light splitting face and the reflection face.