Direct and defuse solar radiations at different heights for clear sky over China have been computed from atmospheric profiles with discrete ordinate method based on the multiple scattering theory.The computed solar radiation at ground are compared with the ground observations obtained at a few national stations of first class.Computed results at heights and the daily variations are also discussed.The purpose of this research is to show that the software,MODTRAN 3,can be directly used to estimate solar radiation parameters for the places short of direct observations.