Abstract:Using the daily precipitation and disaster census data of 76 meteorological stations in Hubei from 1960 to 2005, this paper studied the spatio temporal distribution and disastrous laws of drought and flood. The results show that the frequent occurrence area of drought presents an east west zonal distribution, while the annual occurrence frequency and area of flood are significantly less than those of drought. The annual average drought and flood disasters show opposite variation trends after 1996 in which droughts were more experienced but floods became less. Both of the two disasters concentrate in summer. In addition some areas of Hubei suffered from serious drought disaster continously from 1996 to 2001. The cumulative effect of the drought disaster caused the agricultural economic loss to be leapfrog growth, reaching the maxima in 2001. The flood disaster causing intensity is quasi periodic oscillation. The damaged areas of agriculture crops and agricultural economic losses reach maximum values in the 1990s with correlation coefficient being 0.80. So, positive correlation exists between the flood affected population and direct economic loss. The increasing speed of direct economic losses is accelerated with increasing flood affected population, while the abilities to prevent flood disaster are also strengthened. The drought flood abrupt alternation mainly occurs in the northwest and southeast of Hubei in summer. During sharp turn disaster processes, as drought strengthens the vulnerability of crops and causes serious economic loss in the early period, the increasing speed of agricultural economic losses is accelerated with the growth of disaster affected areas, but the agricultural economic loss would be less than the losses separately caused by droughts or floods.