Northwest China lies in the Eurasia hinterland, which is one of the driest regions as compared with the areas in the same latitude. If drought persists,it will have a severe impact on social and economic development of the northwest region. Therefore, study of drought characteristics in Northwest China is of great significance to the eco-environment improvement and the promotion of economic development in the region. Standardized precipitation evapotranspiration index(SPEI) combining the influence of temperature on evapotranspiration is a new ideal indicator in the research on drought under the background of global warming. The data from 149 representative meteorological stations in Northwest China in 19592011 were used to analyze the temporal and spatial variation of drought. Results showed that drought was a universally existed fact in the northwest. From the inter-annual perspective, the region showed a drought trend with an abrupt change in 1996. Form the seasonal changes,the weather became drought in spring, summer and autumn, and had a humid tend in winter, which is not obvious. Worsening trend occurred in spring, summer and autumn,but was not obvious in winter. Spatially, most regions had a drought trend in spring and summer and a humid tend in winter. Compared with almanac data, SPEI, as a drought index, is confirmed to be applicable in Northwest China.