Abstract: This paper adopts a method of numerical simulation, taking Huangmaohai estuary as calculated example, to calculate tidal deformation due to shore reclamation.Through veri-fication of the measured hydrographic data by the use of the mathematical model,various project schemes of shore reclamation in Huangmaohai estuary are tested for comparison.The results of calculation are: difference of the range of tide and change of the tidal water volume are inversely proportional to the scale of shore reclamation in the bay,and change of the flow velocity distribution is related to the situation and form reclamation.