Based on the meteorological disaster loss data of storm floods in nine provinces of southeast China from 1972 to 2013, the proportions of the disaster-affected areas and disaster-destroyed areas were integrated to establish relative storm flood disaster index, and storm flood risk assessment model was thereby constructed to analyze the risk change of storm flood disasters in southeast China before (1972- 1992) and after (1993-2013) climatic warming, according to grey correlation method and normal information diffusion method. Storm flood disasters in the nine provinces showed a mutational change in the 1980s, which was earlier than climatic warming (1993). The maximum relative disaster index was detected in the 1990s in the nine provinces. The probabilities of severe and moderate disasters substantially increased,while the probabilities of light and small disasters showed an opposite tendency. In general,moderate disasters occurred with a high frequency (less than two years). The frequency of severe and over-severe disasters after climate warming was 2-8 times high as compared to that before climate warming in all provinces,except Jiangsu Province. Considering the effect of tropical cyclones on storm flood disasters,the relative disaster risk index in southeast China was generally increased after warming,except that there was a decrease of 7% in Jiangsu Province. The most significant increment was found in Guangxi Province (by 21%), and the high risk center moved from Guangdong Province to Guangxi Province after climate warming.