The urbanization's effect on risk distribution caused by water logg ing disaster is analyzed in this paper, the basic theory and verification of the water logging simulated model are also introduced. Analyzed the distribution of the rain grade in Tianjin city, according to feature of the storm and the drain ing rule, different types of the rain are numerically simulated with the water l oggi ng simulated model, and the risk caused by the water logging is also primarily e stimated.