By using the data from 8 Indian radiation-sounding stations during the MONEX of May-August 1979 and the radiation measurements during the QXPMEX(the Qinghai-Xizang Plateau Meteorological Science Experiment)conducted during thesaid time and from August 1982 to July 1983, a useful expression for downward atmo-spheric radiation is presented through detailed discoussions. The expression is marked bydistinct physical implications, higher fitting accuracy and considerable universality. The regime of the downward atmospheric radiation is calculated for the first time for 218 sta-tions in the meteorological network of China and investigation done of its geographic dis-tribution and variation with latitudes, elevations and seasons, thus bringing about someinteresting results.