Based on the 0 5°×0 5° monthly average reanalysis data of the ERAInterim Global from 1979 to 2015, this paper calculates the relative contributions of local changes, divergence, advection and verticalterm of water vapor in the water vapor budget equation for the QinghaiTibetan Plateau, and analyzes their variation characteristics. The results show that: (1) In the whole layer and the surface layer, the divergence term of water vapor had the highest proportion in the variation term of atmospheric precipitable water; in the middle and upperlayer, the advection accounted for the highest proportion. There was a better relativity between divergence and precipitable water vapor. (2) The overall spatial distribution characteristic of water vapor divergence was lowlayer convergence and upperlayer divergence; in the whole layer and surface layer, there was moist advection in the eastern part of the plateau, and there was dry advection the rest of the region. In the middle layer, the moist advection region was large, and there was dry advection almost in the upper layer. (3) The interannual variation of water vapor divergence showed an increasing trend, in which the increasing trend was the most obvious in the whole layer, surface layer and the middle layer; and the interannual variation of the water vapor advection showed a downward trend in the whole layer and the other three layers, most obvious in the middle and upperlayer.