The dikes of Poyang Lake protect people's life and property in the lake area,and their reasonable flood overtopping risk assessment are of great significance.Taking the Yanhe dike of Poyang Lake as an example,based on the connotation of dikes overtopping risk,this paper establishes the calculation model of dikes overtopping reliability through reliability theory,and applies the model to the Yanhe dike.According to the calculation results,the relationship between relevant risk factors and dikes reliability is analyzed,and it is concluded that the overtopping reliability of the Yanhe dike is qualified.The research results provide technical reference for the overtopping risk analysis of the dikes,and also provide important guidance for dikes reinforcement and emergency management.