Drought is one of the major natural disasters in the Loess Plateau.In order to reveal the variation law of drought in the Loess Plateau,the observed daily precipitation data of 1961~2012 from 72 weather stations within the study area and around it are obtained by taking the region as the study object,and then the temporal and spatial distribution characteristics of the drought in the Loess Plateau in the recent 52 years is analyzed with the neural network algorithm and the method of mathematical statistics by taking the number of successive effective non-precipitation days as the drought index.The result indicates that(1) The number of the occurrences of different grade droughts in the Loess Plateau significantly changes within a year,while the occurrence number of mild drought is relatively more in spring and summer,the changing trends of the occurrence numbers of moderate drought and severe drought are similar and both of them are prone to occur in winter and the occurrence numbers of most of extraordinary droughts are concentrated in spring.(2) In recent 52 years,the changes of the droughts in different types of sub-regions are also significant,while the occurrence numbers of the droughts in all the sub-regions integratedly present increasing trends,and that the occurrence numbers of the droughts in all the sub-regions from 2001 to 2012 are the maximum among them.(3) The total occurrence number of the droughts in the Loess Plateau and the occurrence number of the droughts in spring therein integratedly present the trends of gradual increase from the southwest to the northeast,while most of the droughts in summer occur at the north border of the Loess Plateau,moreover,the regions with more occurrence numbers of drought in winter are the hill and gully areas in the northwest of the Loess Plateau,the river terraces of Shaaxi,Gansu and Ningxia as well as the north of the gully areas of the plateau,Fenhe River Plain and the hill-gully areas of Shanxi and Shaanxi;moreover,the droughts occurred in winter integratedly present a planar distribution.(4) The occurrence numbers of both the mild and the moderate droughts are generally similar,i.e.all of them present gradual increase trends from the southwest to the northeast,while the most of the severe droughts occur at the north border of the Loess Plateau and most of the extraordinary droughts occur at the northwest hill-gully areas of the Loess Plateau as well.The study result has a certain referential value for making the policy of disaster prevention and reduction for the Loess Plateau.