Abstract: Altay Prefecture in Xinjiang, west China, is of arid climate. Though its latitudes are a little northern, its solar energy is abundant because of long sunshine duration. Based on the theoretical calculation and analysis, in this paper a linear empirical equation of astronomical solar radiation was developed, and it was reckoned according to the latitudes. The computer software developed is convenient for calculation. The practical values and precision of solar radiation in Altay Prefecture were confirmed, and the distribution of astronomical solar radiation and ground total solar radiation was comprehensively analyzed and assessed. According to the calculated results, the annual total solar radiation energy in the Ertix River and Ulungur River basins varied from 5 400 MJ·m^-2 to 5 700 MJ·m^-2. Since 1960, the total solar radiation had been in a decrease trend with a decrease rate of -4.836 2 MJ·m^-2·（10 a）^-1, but it has begun to increase from 1999. The desert area between 45° N and 46° N is characterized by seldom precipitation, low latitudes and high solar radiation, so the solar radiation may be as high as 5 900MJ·m^-2, and the potential solar radiation resources are very high.

Key words: solar radiation, solar energy resources, Altay Prefecture, Xinjiang