Abstract: Based on the NCEP/NCAR re-analysis climate data,the advection and convergence of atmospheric water vapor transport over the northwest China are analyzed.The results are as follow Over the most part of the northwest China,the water advection transport is of negative value,and the inflow water vapor from windward is less than that of the outflow,so it is the net water vapor loss region here.There is the large-scale negative value area of the water convergence over the miidle part of the northwest China and its local water vapor is diffused outward by the wind field only to aggravate water loss,so it is the diffuse region of water vapor.For inter-annual variation of the net water vapor transport,there is less value over the northwest China than that the north China.The advection transport shows the trend of increase while the convergence transport decreases,so the contribution of the advection increases over the northwest China For the correlation to atmosphere circulation,the water vapor advection transport over the northwest China is mainly affected by the westerly,the water vapor convergence transport has the distinct relationship with the South Asia Summer Monsoon The above variation trend suggests that effect of the westerly is increasing.