The invention provides a projection device, which comprises a first light source, a second light source, a light combination element, a diffusion sheet and an actuating element. The first light source provides a first light beam; the second light source provides a second light beam; the first light beam and the second light beam are incident upon the light combination element, and are mixed into a mixed light beam in the light combination element; the diffusion sheet is arranged on the surface of the light combination element; and the actuating element is arranged on the light combination element to actuate the light combination element.