Abstract: Ocean waves of large wave height may bend and break a hull because of the structure collapse. The method to accurately predict the nonlinear dynamic strength of a hull structure in the large waves has become a new research direction of ship structure. A numerical simulation method based on 3 D potential flow theory and nonlinear dynamic FEM is devised for the research. Wave loads are calculated following potential flow theory. The elastoplasticity and buckling deformation of a hull structure are solved by FEM. A series of model tests to verify the accuracy and reliability of the numerical simulation method are carried out. The test model which can produce structural collapse response in tank wave is actually a normal one except its midsection is replaced by a buckling hinge structure. The elasto-plastic characteristics of a hull structure are simulated by the buckling hinge structure. The relation between rotation angle and nonlinear vertical bending moment on the buckling hinge, in tern, vertical bending moment on the model is obtained by performing a four-point bending test and simulations. The calculated results are compared with the test results.