Taking the Gaoqiao hydrological station as a study object, based on the practical data and using themethod of statistics and relation analysis,this paper sets up several storm surge increment models, and 2-D coupling numerical models of the storm surge and astronomical tide at the Yangtze River Estuary,accortling to the hydrodynamics theory. After designing the patterns of the extreme typhoons affecting possibly the estuary by themethod of the effecting factors combination and typhoon displacement,the maximun increment and highest tidal levelare calculated.Finally,this study has given a PMT of the extuary in the near future.