Abstract:The historical data about flood disaster was collected,reorganized and analyzed in upper reaches of Hanjiang River during the historical period(208BC-2010AD).By using least squares method,wavelet analysis,and the Kriging interpolation,the times when flood disaster occurred(stage,seasons,cycles,etc.),the spatial variation and the causes of flood disaster were studied.The results showed that,during the past 2 220years,the flood disaster mainly occurred in the summer and Autumn(May to September)by 336times with a frequency of once every 6.6years in the upper reaches of Hanjiang River.The flood disaster could be divided into 4classes,mild,middle,great and serious floods,and each class accounted for 24.7%,29.5%,40.5% and 5.3%in the total numbers of floods,respectively.Wavelet analysis showed that,the period of each class was 2~5a,38~40a,120a,and 160a,respectively.The floods showed an increasing trend,and could be broadly divided into three stages.There were three flood-prone periods,the early Qing Dynasty of Emperor Daoguang's Reign,Qing Dynasty of Emperor Guangxu's Reign,and the Late Republic to the end of the 20th century.Flood disasters varied significantly at spatial scale,which were declined from Ankang Basin to periphery,and there are two high-frequency centers and two low-frequency centers.Atmospheric circulation anomalies,special terrain conditions,the river's water system characteristics,the degree of bending of the river and the impact of human activities are the main causes of flood disasters in this region.