Projector and lighting system thereof

The invention provides a lighting system which comprises a first excitation light source, a second excitation light source, a lens set, a light splitting device and a fluorescent rotating wheel. The first excitation light source and the second excitation light source respectively emit a first excitation light beam and a second excitation light beam. The lens set has an optical axis and a light-through cross section perpendicular to the optical axis. The light splitting device comprises a first light splitting layer and a second light splitting layer. The area of a projection region jointly formed by projection of the two light splitting layers on the light-through cross section in the direction parallel to the optical axis is larger than 1/4 of the area of the light-through cross section and is smaller than 1/2 of the area of the light-through cross section. The fluorescent rotating wheel can receive the first and second excitation light beams passing through the lens set and is provided with a reflecting reg