To study the influence of different rainfall control methods on the design parameters of the low impact development (LID) system, a case study of Jiangsu Province was carried out. The precipitation data of 70 national meteorological stations from 1961 to 2019 are used for the analysis. The results show that under the same control rate, the designed daily rainfall depth under the mode of volume capture ratio of annual rainfall is greater than that under the mode of event capture ratio of annual rainfall, which is more so in areas with more heavy rains. Moreover the difference increases with the increase of the control rate. Also, the designed rainfall depth of the two rainfall control methods are proportional. The ratio of designed rainfall depth corresponding to 85% volume capture ratio of annual rainfall and that corresponding to 90% event capture ratio of annual rainfall is 1.08. However, the spatial distribution of the initial rainfall control rate of the two rainfall control methods is quite different. The initial rainfall control rate of volume capture ratio of annual rainfall decreases from south to north, with an obvious distribution pattern, whereas that of event capture ratio of annual rainfall is more complicated. The higher the proportion of heavy precipitation, the greater the differences between the two rainfall control methods in aspects of designed rainfall depth, initial rainfall control rate, optimal control rate and optimal designed rainfall.