Abstract: Based on the two-stream approximation a broad-band parameterization scheme for solar radiative flux calculation is presented.The whole solar spectral region from 0.2 to 4.0 μm is divided into three broad spectral intervals.The effective broad-band optical depths and single scattering albedos in the atmosphere in each spectral interval can be obtained using parameterized formulae from known atmospheric parameters.The overlapping scattering or/and absorption effects of two atmospheric constituents are considered properly.In the consideration of radiative effect of clouds in the atmosphere the single scattering albedos and back scattering parameters of clouds in each broad spectral intervals are given preliminarily and the cloud optical depths are determined according to the cloud liquid water content.