In order to design a wide spectral range and ultra wide-angle optical system that is suitable for spaceborne and meet the requirements of the global atmospheric aerosol monitoring. And to solve the problem of image surface uniformity of the wide- angle lens. The inverted telephoto structure is selected according to the performance requirements, the relationship between the angle magnification parameters of the former group and aberration control and rear cut-off distance is analyzed in theory. The pupil aberration that affect the illumination of image plane is also analyzed. Infer that increasing the angle magnification of the former group is unnecessary for getting great aperture coma. Through the use of low dispersion glass and parabolic lens, the optical system is designed and the spectral coverage is 443~910 nm, The F number is 4.5, full field angle of view is 118.8°, the distortion is less than 10%. Each band modulation transfer function (MTF) is more than 0.75@20 lp/mm. Simulation analysis is carried out on the relative illumination of system imaging using the sequential and non sequential methods respectively, the results of the two methods are consistent, show that image plane illumination uniformity of the system is better than 95%, the indicators meet the requirements.