Spatial and temporal distributions of droughts/floods were investigated using the precipitation datacollected at 12 meteorological stations in the Weihe River basin during the period of 1960-2010.Thedrought index(Zindex)is used to describe the characteristics of droughts/floods.Six large-scale droughts orfloods were detected within the whole catchment during the last 51years.Droughts occurred more frequentlyat Huanxian and Pingliang station

while more floods events were found at Changwu and Xiji stations.Ingeneral

there were more floods in the mid and lower reaches of the Weihe River Basin.The majority offloods were observed in the period of 1965-1970and 1980-1985

and the droughts were detected mostly in1970-1975and 1985-2000.Relative wet period were 1960-1968and 1977-1985with higher than averageannual precipitation

which was less than average during 1970-1974and 1992-2001.The Zindices wereanalyzed by empirical orthogonal function(EOF)method at the climate stations.The results showed thatspatial distributions of droughts and floods were mainly influenced by the center of the basin.Due to the topographical effects

the frequency of droughts was higher in the northwest

and that of floods was higher inthe southeast.The heterogeneities of droughts/floods were influenced by not only climate changes and largescale weather system

but also other factors such as geographical location

topography and so on.