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 1959-2011 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.