An illumination system, comprising: - a plurality of laser light sources (112G, 112R, 112B1, 112B2) including a red laser light source for emitting red laser light, a green laser light source for emitting green laser light, a first blue laser light source (112B1) for emitting first blue laser light and a second blue laser light source (112B2) for emitting second blue laser light, wherein the laser light sources comprise a first laser light source, wherein the first laser light source is one of the red laser light source and the green laser light source and the first laser light source is disposed on an optical axis; - a first color wheel element, disposed on the optical axis and on a transmission path of the laser lights; - a plurality of light combiners (D1, D2, D3) including a first, a second and a third light combiner, disposed on the optical axis and between the first laser light source and the first color wheel element, and pervious to the laser lights or reflecting the laser lights, wherein the light combiners (D1, D2, D3) combine the laser lights on the optical axis; - a second color wheel element disposed on a transmission path of the second blue laser light and adapted to convert the second blue laser light into a yellow light, and to output the yellow light to the first light combiner; wherein the first light combiner is pervious to a first laser light (LR; LG) emitted by the first laser light source (112R; 112G) and to the second blue laser light, and reflects the yellow light; wherein the second light combiner is pervious to the first laser light (LR; LG) and to the yellow light, and reflects the other of the red laser light and the green laser light; wherein the third light combiner is pervious to the red laser light, to the green laser light, and to the yellow light, and reflects the first blue laser light; and wherein the first blue laser light source (112B1) is configured to emit the first blue laser light onto the third light combiner and the second blue laser light source (112B2) is configured to emit the second blue laser light onto the second color wheel element, and wherein the first and the second blue laser light sources (112B1, 112B2) are disposed on the same side of the optical axis and the second color wheel element is disposed on the other side of the optical axis. - a plurality of laser light sources (112G, 112R, 112B1, 112B2) including a red laser light source for emitting red laser light, a green laser light source for emitting green laser light, a first blue laser light source (112B1) for emitting first blue laser light and a second blue laser light source (112B2) for emitting second blue laser light, wherein the laser light sources comprise a first laser light source, wherein the first laser light source is one of the red laser light source and the green laser light source and the first laser light source is disposed on an optical axis; - a first color wheel element, disposed on the optical axis and on a transmission path of the laser lights; - a plurality of light combiners (D1, D2, D3) including a first, a second and a third light combiner, disposed on the optical axis and between the first laser light source and the first color wheel element, and pervious to the laser lights or reflecting the laser lights, wherein the light combiners (D1, D2, D3) combine the laser lights on the optical axis; - a second color wheel element disposed on a transmission path of the second blue laser light and adapted to convert the second blue laser light into a yellow light, and to output the yellow light to the first light combiner;