In this paper, the performance of offshore wind turbine structures under long-period wave impacts is investigated, and a numerical model of long-period waves is developed to simulate the wave motion and fluid seepage in the pore medium by using the VARANS equation with the OlaFlow solver, and various turbulence models such as the model, RNG model, and the VOF method is applied to capture free surfaces, which can accurately simulate wave generation, propagation, reflection, breaking, and fluid seepage in the pore medium. These methods can accurately simulate the wave generation, propagation, reflection, breaking, and fluid seepage in the pore medium, and the accuracy of the numerical simulation is verified by comparing the results with those of the physical experiment. The results show that the wind farm exhibits good impact toughness under the influence of long period waves, and its overturning stability and slip stability are better than the safety coefficient required by the specification.