Based on the daily precipitation data from 86 meteorological stations in northwest oasis during 1960-2011, using the methods of equivalent dry period(EDP) and inverse distance weighted interpolation(IDW), the variation characteristics of drought in northwest oasis was analyzed. The results indicated as follows: the annual EDP in northwest oasis presented a decreasing trend, and the change tendency of EDP being -1.109/10 a. In 52 years, the maximum value of EDP presented in 1991, and it reached 108.9 d. The seasonal EDP in northwest oasis presented a decreasing trend, and spring was the most significant. The abrupt change of EDP happened in 1976 and 1996, respectively. Morlet wavelet analysis of EDP in northwest oasis showed that there were periods of 13, 12, 9,13, 10 a in five regions of northwest oasis. The difference of spatial distribution of drought in northwest oasis area is obvious, AWTP index and quite dry period both show that the drought centers are in northwest of Tarim basin and Turpan basin-southeast of Tarim basin-west of Tsaidam basin, and it was decreased from the two centers to the surrounding.