One of the important direction of the optical system is the co-aperture optical system, which takes advantage of optical system characters with long-focus and high resolution. This paper designed a tracking guiding system whose aperture of the optical system for visible light imaging, laser imaging and laser ranging was shared. The co-aperture design combined the high resolution visible light system with high resolution laser system, which made the system not only obtain high-definition images, but also get the relative location information. The co-aperture optical system could compress system size, reduce the rotational inertia when the optical system was in the process of tracking for the overall implementation of the system. The focal length of visible light subsystem is 1 200 mm; F number is 6; field of ±1.2. The focal length of laser imaging subsystem is 1 500 mm; F number is 7.5. Each system imaging quality is close to the diffraction limit, and tolerance allocation results is verified by tolerance analysis.