Under the background of global warming, the climate in arid areas of Northwest China in the past 50 years has changed correspondingly, giving great impacts on the local ecological environment. Based on the meteorological data of 128 stations from 1961 to 2010, and by using DEM and GIDS interpolation methods, this paper approached the characteristics of climate change in the arid areas of Northwest China and their effects on the local ecological environment. In the study areas, air temperature had a rising trend, but the variation range differed with reason and region. The warming trend was most apparent in winter, but slowed down in summer. Regionally, Ili valley and Tacheng had the greatest warming rate, followed by East Tianshan Mountain area and Qilian Mountains. Precipitation also presented an increasing trend. The annual precipitation and winter precipitation increased significantly, spring precipitation had a gradual increase, whereas autumn precipitation increased slightly. The precipitation varied greatest in mountainous areas, but presented a downward trend in the eastern part of the arid areas, the desert hinterland, and its surrounding areas. The climate warming and wetting trend in the arid areas of Northwest China in the past 50 years led to the glacier melting in summer, giving greater effects on the local water recourses and ecological environment, whereas the decrease of the frequency of sandstorm in the study areas was mainly related to the variations of climate from warmdry to warmwet in the desert source regions of Xinjiang and Inner Mongolia, which had definite weakening effect on the occurrence of sandstorm. The fluctuations of lake area and its water level were in some extent the responses to the climate change.