In this paper, dynamic analysis models were constructed for two types of support structures designed to support 3 MW offshore wind turbine towers, and the seismic responses of the wind towers to measured earthquakes and artificial earthquakes were estimated and compared. The two types of support structures compared are the bucket foundation and the jacket foundation, and the ground was considered by soil springs with equivalent stiffness. The mass of the in-member water and the hydrodynamic additional mass for the submerged part were also considered in the analysis model. The two types of support structures that were compared were a ground spring with a bucket foundation and a jacket foundation and the ground with equivalent stiffness. For the analysis, the mass of the adjacent fluid and the hydrodynamic additional mass for the submerged part were considered in the model. As a result, the dynamic model of the wind tower combined with the two types of support structures showed that the dynamic behavior of the superstructure dominates the overall behavior, and the influence of adjacent fluids can be neglected.