An optical projection apparatus is provided, where a reflective light valve, a light deflecting device and a lens set are arranged on an optical path of the light beam providing by an illuminating system. The light deflecting device is located between the illuminating system and the reflective light valve, and the lens set is located between the reflective light valve and the light deflecting device. When the light beam is incident to the reflective light valve through the light deflecting device and the lens set, the light beam is converted into sub-image beams, and then the sub-image beams are reflected to the lens set. The projection lens set arranged on an optical path of the sub-image beams has a pupil located on the light deflecting device. The lens set converges the sub-image beams on the pupil and then the sub-image beams are incident to the projection lens set for imaging.