Influenced by climate change, heavy rainfall and waterlogging have shown an increasing trend in recent years. The distribution system with a small power supply radius and insufficient flexibility in location selection is prone to large-scale power outages caused by waterlogging. Analysis points out that due to the lack of detailed records of waterlogging levels, there is a benchmark missing problem in the planning and construction of distribution systems in terms of waterlogging protection. Therefore, referring to disaster prevention methods such as ice disasters in power systems, and based on the analysis of storm inundation using a two-dimensional hydrodynamic model, this study proposes a method for delineating and differentially planning power outage risk areas in distribution systems due to rainstorm and waterlogging, considering the impact of micro-topography. Firstly, extreme rainfall for different return periods is estimated based on the extreme value distribution model, and then combined with geographic information for two-dimensional hydrodynamic simulation to obtain inundation maps, including inundation scope and depth, for extreme rainfall with a 50-year return period. Secondly, considering the construction standards of distribution terminals such as distribution transformers and switch stations, power outage risks corresponding to different inundation depths are set, and then a risk level map of power outages in the distribution system due to rainstorm and waterlogging is drawn. This provides a basis for setting different foundation heights for distribution terminals in different risk areas, enhancing their resilience to rainstorm and flood disasters. Finally, the effectiveness of the proposed method is verified through simulation analysis based on data from Nanning.