Abstract: According to the development demand of miniaturization and lightweight for airborne photoelectric weapons, an infrared and laser system was designed with the common optical path. The infrared waveband of the system was 3 μm~5 μm, and the F number was 2. The surface array detector with a medium wave of 640×512 pixels was adopted, and the pixel size was 15 μm×15 μm. The laser emission and infrared optical path used the common telescopic system. By using cubic prism, the scanning in the range of azimuth 360° and pitch 0°~90° was realized by optical system. The common optical path design could reduce the size of the mirror and lens in the optical path, which had the characteristics of compact structure and small mass. It was focused on the problem of introducing the laser back scattering by the optical elements in common optical path. The joint optimization method of CODE V and LightTools was adopted to avoid its influence, which could ensure the good imaging performance of optical system.