Since the great storm surge disaster due to Typhoon Vera in 1959, the Japanese Government has been constructed coastal defense with the design storm water level including the storm surge of the typhoon or the local highest water level record. Severe storm surge disater, however, repeated in 1999 and 2004. The global mean sea level rise and tropical cyclone intensification due to climate change may increase the frequency of severe storm surge disaster. The deep understanding of recent disasters and the preparedness for unexpected disaster are quite important for future disaster mitigation. Storm surge numerical models should be applied more effectively to three chances: (1) quick prediction at the time of the approach of a typhoon, (2) hindcasting just after the disaster, and (3) discussion on the safety degree of coastal defense in usual days.
　This paper, therefore, started with the lessons learned from recent storm surge disasters in Japan, Korea, and the United States, and then improved three types of storm surge numerical models.
　(1) A suitable computational condition was selected for the quick prediction of the storm surge at ports at the time of the approach of a typhoon, and then the model was applied to several typhoons. Stochastic storm water level prediction was also examined.
　(2) The marine surface wind field was caluculated with a good precison by modifying an empirical typhoon model or introducing the meso-scale meteorological model. Then the storm surge numerical model with the wind field was coupled with astronomical tide and wave models for the precise description of storm surge phenomena.
　(3) The methodology of evaluating extreme storm surges with a stochastic typhoon model was disussed. Then the return period of the current design storm water level was evaluated under the current and future climates.