Abstract: There was an abnormal temperature increasing process for 9 days in northern Xinjiang from Jan. 27 to Feb. 4 in 2007. The day maximum temperature in $1/3$ stations has passed the historical extremum of the corresponding period and the average temperature during these 9 days in 44.2 percent of stations has done too. The last ten-day of January should be stable snow accumulating period but the appearance and standing of temperature increasing process led to snow melting earlier in northern Xinjiang in 2007 and snow area of counties of Bortala Prefecture, Ili Prefecture, U num qi City, etc decreased evidently, especially the snow coverage rate of U num qi City is only 25.84 percent about 50 percent of the average for last 15 years of the corresponding period. Winter is a season with maximal temperature increasing amplitude; while in the background of climate warming up there are more and more extreme weather or climate events, the higher temperature coming from abnormal increase caused the quicker melting of snow in northern Xinjiang. These changes result in a great deal of inestinable influences on the space-time distribution of water resources and ecological environment. It is necessary to intensify the monitoring of extreme weather or climate events and analyzing their influences on ecological environment economy and society development and so on so that the results of climate changes would be understood scientifically and impersonally which is helpful to put forward the count measures against regional climate changes and reduce the influences

Key words: midwinter abnormal, temperature increase, snow depth, snow coverage rate