Abstract: The paper aims to understand the distribution rule and trend of sunshine hours, and their changing reasons in the Qaidam Basin of Qinghai over the past 50 years. The authors used the statistical method and abrupt change test to analyze the variation characteristics of sunshine hours, based on the monthly data of sunshine hours, temperature, cloud cover, precipitation, wind velocity, vapor pressure from 9 meteorological stations in Qaidam Basin. The results showed that: the annual variation characteristics of sunshine hours in the Qaidam Basin significantly decreased in the whole year and the four seasons, the variation characteristics of sunshine hours reached a turning point in 1990; the distribution pattern of annual sunshine hours decreased from the northwest to the southeast, the maximum value was in the Lenghu station, and the minimum value was in the Chaka station; the distribution characteristics of sunshine hours in spring, summer, autumn were similar to that of annual distribution, though the distribution characteristics in winter gradually decreased from the south to the north; Dachaidan and Golmud were taken as the dividing line of distribution characteristics of the climate tendency rate of annual sunshine hours, there were two obvious decline regions, of which the maximum decrease was in Lenghu and Chaka station; the annual sunshine hours had a mutation in 1995 in Qaidam Basin; the main factor affecting sunshine hours in Qaidam Basin in Qinghai was cloud cover, while the secondary factor was slightly different.