Based on the measured data of 23 climate stationsduring 1959-2014 in Weihe River Basin, compared and analyzed the applicabilityof the standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI) in Weihe River Basin, obtained that stability of SPEI was more better. Afterwards using the SPEI, has researched the drought frequency and intensity, analyzed the spatial and temporal change characteristics of drought in recent 55 years by different time scale in Weihe River Basin. The results showed that: the more time scale, the smaller fluctuation of SPEI. The SPEIwas mutated in 1991, hereafter the drought was become severe, and exsisted about 14 years and 7 years changing cycle in Weihe River Basin. The frequency of yearly scale drought was presented the distribution of high in east and low in west, the maximal drought frequency places above moderate drought were around Xiji, Wugong and Tianshui, the frequencies were 14.28%, 14.28% and 14.28% respectively. From the seasonal scale, the autumn drought frequency was higher than other seasons, the highest frequency of above moderate drought in spring, autumn and winter seasons was in Tianshui Basin, the frequency was 21.4%, 19.6% and 8.9% respectively. The highest frequency of above moderate drought in summer season was inPingliang, its frequency was 16.1%. As a whole the distribution of monthly scale drought intensity was decreased from east to west, among them the biggest drought intensity was at the south Foping region, the drought intensity was 30%. Inrecent 55 years, the Tianshui and Haiyuan Regions were occured the maximal numbers of continuous drought process, can be reached 22 years. The month numbers ascontinuous drought process were mostly for 3 to 4 months, but there were one time of 9 months long continuous drought process in Wuqi station.Through the research for all kinds of drought characteristics by multiple time scales in this river basin, in order to provide guidance for drought control and resistance.