For the protection of a coastal nuclear power plant (NPP) against external flooding hazard, the risks caused by natural events have to be taken into account. In this article, a methodology is proposed to analyze the risk of the typical natural event in China (Typhoon). It includes the simulation of the storm surge and the strong waves due to its passage in Chinese coastal zones and the quantification of the sequential overtopping flow rate. The simulation is carried out by coupling two modules of the hydraulic modeling system TELEMAC-MASCARET from ElectricitØ de France (EDF), the shallow water module (TELEMAC2D) and the spectral wave module (TOMAWAC). As an open-source modeling system, this methodology could still be enriched by other phenomena in the near future to ameliorate its performance in safety analysis of the coastal NPPs in China.