Abstract:1980′s, the serious arid area with dryness index below 10 didn′t exist in Xilinguole League. The dominant climate zone was the moderate arid one which accounted for 40.63% of the total area, at the same time, wet arid zone made up nearly 20% of its total; Into the 90′s, dry and moderate arid areas slightly reduced, but wet arid areas increased to 2158% and the drought wet areas took up 11.90%; The early 21st century, the climate for most parts of Xilinguole League showed a general tendency with Idm value declining and drought degree rising, dry arid zone occupied a dominant position on the spatial distribution, and the original climate pattern with alternate strips was broken, too. Along with the temporal process, the spatial range of different aridity classes had changed and the changes were particularly notable in the 21st century. Compared with 1980′s, the position of three aridity contours of 22.5, 25 and 30 had shifted westward slightly, respectively moved for 0.27, 0.05 and 0.25 longitudes in 1990′s, and the displacement for each aridity class was more obvious in the early 21st century. The position of five aridity contours of 15, 20, 22.5, 25 and 30 were shifted eastward for 1.13, 2.66, 1.81, 0.8 and 1.23 longitudes. All of these results showed that the climate in Xilinguole League had a tendency with aridity degree increased since the beginning of 21st century, and the spatial range for each aridity class took place significant displacement eastward.