The pile foundation of offshore wind turbines is not only subjected to the cyclic action of wave load, but also the threat of seismic load. Therefore, the environment of pile in the ocean is complex. However, most theoretical investigations have often focused on the seabed response at water wave load or seismic load respectively. In this paper, a wave-seismic-pile-seabed coupling model is constructed by using the finite element method. The numerical analysis is based on the implicit dynamic analysis in Abaqus. Morison’s equations are used to simulate the effect of water wave on pile foundation. The Mohr-Coulomb model is adopted to simulate the seabed while the pile is considered as an elastic medium. The earthquake is applied on the bottom of the model as acceleration. The dynamic response of the pile embedded in seabed are studied, such as acceleration, displacement, shear force, and bending moment. The results show that seismic load has an important influence on the single pile foundation of offshore wind turbine. Under the action of earthquake load, the acceleration and displacement response of the pile are amplified to a certain extent. The properties of the soil and the parameters of the pile are crucial to the design of the single pile foundation for offshore wind turbines.