Abstract: High resolution spatial and temporal distribution of the solar radiation resources in China in the past decades is simulated using the fifth generation Penn State University/National Center for Atmospheric Research (PSU/NCAR) Mesoscale Model (MM5), and its parameterization schemes are determined according to the numerical sensitive experiments results. The daily radiation observation data from 1975 to 1997 with good quality control is used to validate and evaluate the model performance, and to improve the simulation of the solar radiation with the optimal interpolation method, after which the mean absolute normalized gross error (MANGE) has decreased from 24.4% to 8.5% and the normalized mean bias (MB) has decreased from 20.6% to 3.5%.The simulated spatial distribution of the solar radiation shows that the solar radiation of the whole country is 5648.6 MJ/m² per year on averge. The solar radiation is higher in western regions than in east, divided by the line from the middle western of the Inner Mongolia, to Ningxia, northwestern Gansu, western Sichuan and northwestern Yunnan provinces. To the west of this line, the radiation is more than 6000 MJ/m² and to the east, the solar radiation in North China is highest. The inter annual variability tendency of the radiation from 1975 to 1997 is increase—decrease—increase, with the highest annual radiation in 1978 and the lowest in 1989. The solar radiation in each province is calculated from the simulated radiation after the optimal interpolation with the Geographical Information System (GIS) tools (based on ArcGIS 8.3 desktop) and classified according to their solar radiation resources. Tibet, Qinghai, Xinjiang provinces have the most solar radiation resources in China, and the averaged solar radiation in Tibet is more than 6900 MJ/m² per year.