The east-central China is a major agricultural region with dense population and developed economy. The region is also with abundant precipitation which causes severe flood damage each year. Daily precipitation data from 292 meteorological stations in east-central China for the period from 1961 to 2008 and annual crop affected area, disaster area and plant area of 17 provinces between 1971-2009 were used to construct rainstorm climatic index and its risk assessment model, then, the maps of rainstorm climatic risk and its geographic distribution in east-central China are compiled. The results show the assessment of disaster grade coincides with actual disaster situation. In time scale, the rainstorm climatic index matches well with relative disaster index; the correlation coefficient between the rainstorm climatic index and the agricultural relative disaster index for each of the provinces except Guangdong (0.5) is more than 0.6. The rainstorm climatic index and relative disaster index are high in the south areas and low in North China. The distribution of rainstorm climatic risk and relative disaster risk are not exactly the same, which means the areas with high-value of rainstorm climate risk may not be the areas with the severe disaster. The reasons may be the different ability of disaster prevention and mitigation.