A beam splitting module is disposed on a base plate of a light source system, and includes a supporting wall, a beam splitting lens, and a biasing member. The supporting wall has a first wall surface, and is disposed on the base plate such that the first wall surface extends perpendicularly from the base plate. The beam splitting lens has a first lens surface disposed adjacent to the first wall surface of the supporting wall, and a second lens surface opposite to the first lens surface. The biasing member is secured to the base plate, and is disposed adjacent to the second lens surface of the beam splitting lens for urging the beam splitting lens toward the supporting wall such that the first lens surface of the beam splitting lens abuts against the first wall surface of the supporting wall.