Based on DEM data of 1:250 000 scale and the data from 145 routine observation meteorological stations in Henan Province from 1961 to 2000,after fully considering the sky and rugged terrain elements,the paper realized the simulation of the spatial distribution of diffuse solar radiation(DSR) over rugged terrain in Henan Province with the extraterrestrial solar model and the terrain openness model.Monthly DSR and annual DSR at the resolution of 100 m×100 m over the rugged terrains in Henan Province were calculated.The simulated results show that,after fully considering the spatial-temporal characteristic coefficients,the simulated accuracy can be improved.The observation data from Zhengzhou indicate that the accuracy is high.The annual average error is 3.06 MJ·m^-2 and the annual absolute relative bias error is 1.67%.The local terrain can affect the DSR obviously.The annual average error of case year test is less than 11%.In summary,this model is good in spatial-temporal simulation.