Abstract: In this paper,the humidity indexes are calculated and the time sequences and periods of precipitation are analyzed according to the temporal and spatial changes of precipitation and humidity in north Xinjiang.The changing laws and features of the climate in north Xinjiang are discussed.Furthermore,by using satellite images and according to the field investigation,the paper discusses the normal and inverse developing processes of Gurbantonggut Desert under the peculiar climate and environment based on the interdependent relations of the desert environment and climate changes.The analyzed results show that the climate change is in a warm-dry period since 1950s although the humidity rises and precipitation increases slightly.Moreover,the area of moving dunes enlarges and desertification becomes serious increasingly in Gurbantonggut Desert.It is considered that climate change is the main cause of enlargement of the area of moving dunes in the desert,and artificial factors play the triggering and accelerating roles.In short,desertification caused by whatever factors will bring about a tremendous harmfulness to human's living environment if the control measures are not positively taken.

Key words: humidity index, climate change, environment, Gurbantonggut Desert