A projector and an illumination system are provided. The projector includes an illumination system, a light valve, and a projection lens. The illumination system includes a light source configured to provide an illumination beam and a light processing module comprising a reflective wheel structure and a driving unit. The reflective wheel structure includes first and second reflective structures. The first and second reflective structures are located on a transmission path of the illumination beam. The driving unit is connected to the first reflective structure or the second reflective structure and is configured to drive the first and second reflective structures to rotate synchronously. The light valve is located on a transmission path of the illumination beam transmitted from the second reflective structure and configured to convert the illumination beam from the second reflective structure into an image beam.