Background sky radiation means the spatial distribution of sunlight absorbed and scattered by particles in the atmosphere. It is important in scientific research and engineering applications. Kinds of ground-based instruments for measuring the background sky radiation are introduced. Algorithms of estimating the optical properties of atmospheric aerosol, the column density of water vapor, ozone and nitrogen dioxide as well as the spatial distribution of clouds are reviewed to illustrate the applications of background radiation in atmospheric optics research. It is the reference for the follow-up studies, according to the background spectra radiation in the atmosphere. Several research objectives about environmental perception and weather identification according to the all sky background spectra radiance are proposed.