A light source module includes phase retardation layer, first light source, second light source, first Polarization Beam Splitter (PBS) layer, second PBS layer, first redirector and second redirector. The phase retardation layer, the first light source, the second light source, the first PBS layer, the second PBS layer, the first redirector and the second redirector are symmetrically disposed relative to symmetry axis. The first light source and the second light source each emit polarized light having first linear polarization direction and polarized light having second linear polarization direction. The phase retardation layer converts the first linear polarization direction of polarized light into the second linear polarization direction. The PBS layers allow polarized light having the first linear polarization direction to travel through but reflect polarized light having the second linear polarization direction. The redirector reflects polarized light having the second linear polarization direction.