A light source apparatus includes at least one light source and a light source transforming apparatus. The light source transforming apparatus includes at least one light guiding medium and color-combining medium. The light source transforming apparatus is configured to receive incident light of the at least one light source and then transform the incident light into emergent light emitted from the color-combining medium and into a light integrator, wherein a divergent angle of the incident light is larger than a divergent angle of the emergent light, and a incident area of the light source is smaller than an emergent area of the color-combining medium.