In order to overcome the complexity of the space environment and meet the space operating requirements of the space engineering, a micro space-borne camera optical system of 25-megapixel wide-spectrum confocal imaging was developed. This system adapted to the harsh environment of satellite launch and orbit operation, which had the advantages of impact shock resistance, high temperature and differential radiation resistance in space, small size and light weight. The designed system can be clearly imaged in the spectrum of 450 nm?800 nm, of which the focal length is 181 mm, the entrance pupil diameter is 45 mm, the field angle is 10.4o, the edge relative illumination is 0.81. The modulation transfer function (MTF) is 0.57 at 55 lp/mm and 0.33 at 110 lp/mm, the distortion is 1.2%, the quality of lens is 622 g, the overall dimension is Φ58.3 mm×117 mm and the anti-radiation performance is more than 5 krad. Through the simulation and optimization of the temperature adaptability, the user can perform the thermal vacuum test of ?30℃~+70℃ optical lens normally. This system is successfully applied to the accompanying satellite camera of Tiangong-2 space lab, the obtained images are clear and stable, which plays an important role in the space remote sensing experiment observation.