Abstract: Based on the data of meteorological disaster losses of flood disasters in 12 southern China provinces (municipalities) during 2004-2012, the proportions of the affected area, the affected population and direct economic losses were derived to develop an integrated index of relative flood disaster and flood risk assessment model to assess the flood risk in southern China using grey association and normal information diffusion methods. The three indicators abovementioned eliminated the effect of multiple cropping, population dynamics, rising prices and regional scale restriction. Results showed that the integrated index of relative flood disaster could reveal the variation of flood damage in different provinces of southern China for each year, and the coefficients of correlation between the integrated index of relative flood disaster and the actual flood damage in each province were above 0.7 (P<0.05). Most of flood disasters were small and mediumscale ones. The occurrence probabilities of largescale disaster in Jiangxi, Hubei, Sichuan and Chongqing were much bigger than those in other provinces. By excluding the influence of tropical cycloneinduced flood disasters, the value of the integrated relative flood risk was higher in interior areas than in coastal areas. Flood risk in Hubei Province was the highest in interior areas and the risk in Jiangsu Province was the lowest in coastal areas. This study solved the problems in risk quantification and the comparability of integrated relative disaster grades in different regions, and provided a scientific basis for prevention countermeasures and insurance policymaking of regional flood disasters.

Key words: material flow analysis., sustainable intensification, spatial-temporal pattern, agricultural land, land use intensification