Based on the average and extreme values of maximum 24-hr rainfall for the last 30 years at hydrological and meteorological stations in China, the demarcation of severe rainstorms in China is investigated. The intensities and seasonal distribution features of severe rainstorms, weather systems and the direction of water vapour transfer and some geographical factors, including topography, elevation and the contrast nature of sea and continent, are comprehensively considered for demarcation.First of all, based on synoptic climatology, ten regions, where rainstorms occur, may be preliminarily delimitated.Secondly, by calculating the areal rainfall index of each region, the correlation coefficient of the areal rainfall index with annual rainfall (or precipitation in May-Aug.) at every station in a given region can be computed. If the correlation coefficient reaches the level of significance (a = 0.05) it means that the station belongs in the same climate region.Finally, ten homogeneous climate regions of severe rain storms and four subregions are delimitated. The genesis of rainstorms and its characteristics in each of the regions are briefly dis-cribed.