Abstract: The Tibetan Plateau is a typical area in the global climate system, its climate change Possess sensitive response and strong effect to the global climate change.Based on the precipitation data of the 135 stations on Tibetan Plateau from 1982 to 2001, the use of EOF expansion method to analyze the Tibetan Plateau in the spatial distribution of precipitation and the time evolution of the characteristics and trends, we can find that the annual precipitation of the northern (the Qinghai region) and Southern (Tibet) is mainly concern with the change of north-south RP.In The past 20 years, the annual precipitation of the northern district showed decreasing trend, but the southern district showed increasing trend, the distribution of rainfall in the Tibetan Plateau from the Brahmaputra valley to the northwest gradually decreasing and the precipitation of the lower reaches of the Brahmaputra is the most, the least average annual rainfall precipitation of the northwest of cai da mu Basin is only 17.6 mm.