Projection device, control method of projection device and projection system

The invention discloses a projection device, a projection device control method and a projection system, and relates to the technical field of projection equipment. The projection device comprises an imaging unit used for providing an image bearing light beam propagating along a projection light path; a prism which is arranged on the projection light path, wherein the prism is provided with a light incident surface, and the light incident surface is opposite to the imaging unit and is obliquely arranged; and a light splitting film which is arranged on the light incident surface, wherein at least part of the image bearing light beam is reflected to the first projection surface by the light incident surface to form a first projection image, and the remaining part of the light beam of the image bearing light beam is emitted to the second projection surface to form a second projection image after being transmitted into the prism from the light splitting film. The projection device provided by the invention can re