Abstract: Based on the NCEP/NCAR re-analysis of the climate data,the effects of westerly and monsoon on atmospheric water vapor transport over the Northwest China are analyzed.Mme significant results are showed.There are three obvious sub-regions of the water vapor transport over the Northwest China.The water vapor transport is primary from the southwest monsoon over the region to the south of the (Qinghai-Tibetan) Plateau shear line,and from the westerlies over the region to the north of the Plateau shear line,or from the both above over a saddle region to the northeast of the prolongation along the Plateau shear line.There are some water vapor transport streams from the southwest monsoon span or along the east brink of the Qinghai-Tibetan Plateau.But the water vapor transports are primarly from the peripheral zone to the mainbody over the most of the Qinghai-Tibetan Plateau,and there are no obvious transport stream spans over here.The primary water vapor transport is in the middle troposphere over the region over the north of the qnghai-Tibetan Plateau and in the low troposphere over the southern part of the qnghai-Tibetan Plateau.Over the most of the north of the qnghai-Tibetan Plateau,the water vapor transport is divergent,influent water vapor is again diffused out.The main of theqnghai-Tibetan Plateau and the eastern parts of the Northwest China are the convergence regions of the water vapor transport.The westerly water vapor transport is the basic water vapor source,and the westerly fluctuation has the direct effect on interannual change of the water vapor transport flux divergence over the rmst of the Northwest China.The Ruth Asia summer rmnsoon affects the southern and the eastern parts of the Northwest China by the southwest water vapor transport stream,and the westerly fluctuation by adjusting the circulation,and the westerly water vapor transport for the Northwest China.