Abstract: The storm surge samples are simulated by using numerical model of dynamics and the mechanism is discussed in this paper.The results show that, whether the set up of water level caused by storm increases gradually from south to north along the Zhujiang River is closely related to the strength of the tropical cyclone and to the path of the storm too.Because most of the tropical cyclones are west-going in the South China Sea, this makes they look like passing by storms.The area of Lingding yang for collecting water is not quite large.The river net in the Zhujiang River Delta has the dispersion effect to the water piled up by the storm.These reasons make the set up of water level caused by storm generally no more than 2.5m.Even with this scale of set up the storm surges endanger the safety in this estuary plain.Owing to the coupling of astronomical tide and the shallow water effect, storm surge deforms frequently in various degrees.In the numerical simulation in this paper, the model, parameters and calculation samples were chosen long before; only slight adjustments are required and good result can be obtained.This shows that the modeling is rational and reliable.