Abstract: Hengyang City is an important agricultural production base in Hunan Province.The agriculture was mainly in rain-fed and often suffered from drought and flood risk,especially high risk of drought.The historical disasters were statistically analyzed by using the disaster data in the last 50 years in Hengyang.The results indicated that the agricultural drought hazard occurred more frequently than the agricultural flood hazard in Hengyang.The agriculture drought appeared much in the summer and autumn,while the agricultural flood often occurred in the beginning of the summer and the end of the spring.The frequency of the agricultural drought hazard was bigger in the South than in the North.The Frequency of the agricultural drought hazard was biggest in the middle of Hengyang,while the frequency of agricultural flood hazard was bigger in the North than in the South.The frequency of agricultural flood hazard was bigger in the Xiangjiang River than in the east mountainous region and middle hill regions.The occurrence of serious floods and droughts were forecasted by grey theoretical modeling.The simulated results were consistent with the disasters occurred in 1986-2006.It was forecasted that there would be the risk year of serious drought in 2012 and the risk year of serious flood in 2014.It help to deal with catastrophe in Hengyang City,at the same time help promote the sustainable development of the agricultural economy.

Key words: Agricultural flood and drought disaster, Agricultural flood and drought disaster, Hengyang, Forecast of serious flood and serious drought year