Abstract: The local small and medium-sized rivers in the Plain River Network Area (PRNA) normally have the characteristics like insufficient measured data, complex water systems, obvious artificial influence, low-lying landforms and prone to waterlogging, which are not conducive to the efficient promotion of current flood risk analysis work. Accordingly, based on the principle of water balance and the idea of hydrological zoning, the methods of frequency analysis, unit hydrograph and flood volume calculation were used to carry out a flood risk analysis example under typical adverse scenarios in the Diaocha Lake basin of Hanchuan City. It is concluded that the scheme has the advantages of less data demand, easy data acquisition, mature methods, and convenient calculation, and it is suitable for the application in the data-deficient PRNA where waterlogging is the main problem.