Precipitation is critical for maintaining ecosystem stability, especially in arid regions. This study was primarily focused on the changes during the present (i.e., from 1985 to 2005) and future (i.e., from 2040 to 2059) periods in Xinjiang, northwest China. To predict the future climate, the Weather Research and Forecasting model was run in Xinjiang using National Climate Research Center Community Climate System Model version 4 for the mid-21st century under representative concentration pathways 4.5 and 8.5 (RCP4.5 and RCP8.5, respectively). The results indicate that the amount of annual precipitation would increase in the future under RCP4.5 and RCP8.5 in Xinjiang, especially in the mountainous areas. The increase in precipitation was predicted to be much smaller under RCP8.5 than under RCP4.5, except in Southern Xinjiang. Moreover, the increased precipitation predicted in Xinjiang implies that the current humid and warm conditions will continue. In addition, the largest increase in seasonal precipitation was predicted to occur in spring and summer in Tianshan and Northern Xinjiang, whereas this phenomenon will occur in spring and winter in Southern Xinjiang. In addition, it was predicted that daily heavy precipitation events will occur more frequently in various subregions of Xinjiang, although light rain events will remain dominant. Finally, the increase in the frequency of heavy precipitation events was found to be related to the vertically integrated column precipitation, whereas the relative humidity was observed to be closely related to the changes in annual and seasonal precipitation.