China’s Northern Xinjiang is located in a typical inland arid and semi-arid area，over which anomalous precipitation plays an main role. In recent years, anomalous precipitation events have increased with rising global temperatures. In this study, the inter-decadal variability of the wintertime precipitation in Northern Xinjiang have been investigated by using the observational rainfall data of 40 stations、ECMWF ERA-Interim and NCEP/NCAR reanalysis dataset for 1979-2017. This study discusses water vapor transport characteristics of wintertime snowstorm days and possible mechanisms in four regions based on the HYSPLIT v4.9 model. Our main results are as follows: (1) The west boundary input of water vapor is mainly in each region, but a small amount of water vapor is imported from the northern boundary in the western TianShan, and some water vapor is imported from the southern boundary in the upper in the TianShan; (2) the water vapor passages are mainly located in the Eurasia of the mid-latitude westerlies in the north、the west and the western TianShan, but their exact locations are different. The water vapor transport mainly come from the Mediterranean and the Black Sea in the north, and their contribution ratios are 58.8%; The water vapor transport mainly come from the Southwest of the Caspian Sea in the west, and their contribution ratios are 70.8%; The water vapor transport mainly come from The Black Sea and the Southeast of the Caspian Sea in the western TianShan, total contribution ratios are 72.9%; The water vapor mainly come from the India and the Iran in the TianShan, and their contribution ratios are 64.2%. (3) The geopotential height anomaly shows “+ -”from south to north, and shows “- + -”from west to east in the different regions, but the intensity、the range and the location of the anomaly center are different, this difference leads to difference of influential regions.