In this paper, we used long-term (1979-2007) snow depth dataset of China, which was provided by 'Environmental and Ecological Science Data Center for West China' and analyzed the change of snow depth and distribution on the Qinghai-Tibetan Plateau. The linear regression method was used to study the variation trends of mean snow cover days and snow depth on annual-scale and seasonal-scale. Results show that, first, there were significant positive relationship between either two of the mean annual snow cover days, the mean annual snow depth and elevation. Second, the snow distribution on the Qinghai-Tibet Plateau had a mutation in 1988. Before 1988 there were two different distribution areas, by contrast, three different distribution areas were observed after 1988. It may be caused by the transition from warm and dry period to warm and wet period on the Qinghai-Tibetan Plateau in the mid and late 1980's. Third, we separate the Qinghai-Tibetan Plateau into two different regions based on different air masses in summer. The dividing line was near 34°N-35°N inherited from the research by Tian Lide. In the north, there was a significant increase in mean annual snow cover days from 1979 to 2007 at the rate of 1.40 d/a (R²=0.39,P < 0.01), which was different from the tendency of the whole country. It was mainly caused by the increase in northwest during winter season. In the south, there was a significant decrease in mean annual snow depth from 1979 to 2007 at the rate of -0.04cm/a (R²=0.24,P < 0.01), which was consistent with the tendency of the whole country. It was mainly caused by decrease in southeast during spring and summer and autumn seasons.