Abstract: The Short-duration probable maximum precipitation (PMP) is the main basis for the design of drainage facilities in nuclear power plants. Based on the analysis of the rainstorm characteristics, weather causes and site data of a coastal nuclear power plant site, this paper used the Pearson-III curve and moment method to calculate the numerical statistics of short-duration rainfall with different frequencies, and then calculated and analyzed the ratio of the design value of different durations of once-in-ten-thousands-year rainfall and the design value of 24-hour once-in-ten-thousands-year rainfall to obtain the possible maximum precipitation with different short durations. Finally, by comparing with the records of heavy rainstorms at home and abroad and the short-duration PMP results of other nuclear power plants, the calculation results were reasonable, which can provide reference for the analysis and calculation of short-duration PMP in other regions.