Using the empirical orthogonal function, morlet wavelet analysis, Mann-Kendall rank correlation method and climatic trend coefficient method, the characteristics of temperature on spatial distribution pattern and the multiple-time scale variability are analyzed by the monthly temperature data of 95 sites in the northwest arid area during 1951-2008. Results indicate that: (1) There are 3 years period, 9 years period and 12 years period approximately in research region. (2)Temperature spatial distribution pattern is primarily" Complex type" (to contribution the overall changes rates were 30.93%),according to that, the northwest arid area was divided into northern of Xinjiang region, the southern of Xinjiang region, Qinghai region, Hexi Corridor region and Inner Mongolia Plateau region. For the average annual temperature series, according to level of warm and cold, the rates for normal, abnormal warm, significantly warmer, cold, significantly colder and extreme colder were 44.8%, 15.5%, 3.4%, 13.8%, 8.6% and 8.6% respectively. Since 90s, temperature increase significantly, the positive temperature anomaly value was 6.9℃ for 2001-2008, the ratio of positive anomaly year increased from 40% to 100% since 1980s.(3) There are 97.9% regional appear rising tendency in the research region(94.7% and 96.8% of the stations passed0.01 and 0.05 significance test, warming rate 0.02℃/10a-1.21℃/10a).In the northwest arid area, there are some centers of the warming area, for example, Fuyun(1.09℃/10a) in north of Xinjiang, Kashgar (0.22℃/10a) in south of Xinjiang, Barkol (0.76℃/10a) in east of Xinjiang, Xiao Zaohuo (0.81℃/10a) in Qaidam Basin, Song-shan(0.08℃/10a) in Hexi Corridor and Quixote(0.03℃/10a) in Inner Mongolia Plateau region.