An optical engine is provided, including an imaging module, a driver module and a connecting unit. The imaging module includes an imaging housing with an imaging space and an imaging unit installed in the imaging space. The imaging housing is made of a conductive material. The driver module includes a driver housing with a driver space and a driver circuit board installed in the driver space. The connecting unit includes at least one of the cables is electrically connected to the imaging unit and the driver circuit board and at least a protruding module protruding from the imaging housing (or the driver housing) to contact with the driver housing (or the imaging housing). The cable is installed in the protruding module made of a conductive material.