An optical mechanism includes a bracket, a first polarization beam splitter, a second polarization beam splitter, a plurality of panels and a plurality of lenses. The first polarization beam splitter and the second polarization beam splitter are joined to the bracket. Light passes through the first polarization beam splitter to reach the panels and is reflected by the panels to generate image beams. The image beams are reflected by the first polarization beam splitter to enter the second polarization beam splitter. The image beams are reflected by a splitting surface of the second polarization beam splitter to pass through the lenses and projected by the lenses.