[Purposes] The spatial-temporal distribution laws of design rainstorm between Zhexi Reservoir and Taojiang Hydrological Station (the Zhe-Tao region) in Zishui Basin were investigated with an aim to provide a scientific basis for flood forecasting and flood control operation optimization of cascade reservoirs in the Zhe-Tao region. [Methods] This study used the data of annual maximum rainstorm from 17 rainfall stations with different duration in the past 30 years to analyze and calculate the frequency of station and surface rainstorm. Spatial and temporal distribution laws of design rainstorm in the rainfall station network were analyzed according to the rainfall intensity-duration-frequency curve with different duration and the spatial pattern of the design rainstorm. [Findings] The spatial and temporal distribution of the design rainstorm in the rainfall station network in the Zhe-Tao region is extremely uneven, and the intensity of the design rainstorm increases greatly within a short duration. Spatially the center of the design rainstorm expands from the middle reaches to the lower reaches of the Zishui Basin along with the increase of the design rainstorm return period, and the extent of rainstorm center gradually shrank along with the increase of the design rainstorm duration. [Conclusions] The design rainstorm in the rainfall station network of the Zhe-Tao region of Zishui Basin is characterized by a rapid increase in a short duration and high intensity in the middle reaches. Results of this study provide a theoretical basis for the flood control and safety management of important cities in the downstream basin of Zishui Basin.