Abstract: The dynamic response of a wind turbine system under earthquake action is numerically investigated. First, the physical stochastic model is introduced and the corresponding mean value earthquake record is given. Then an integrated finite element (FE) model of a wind turbine system consisting of the rotor, the nacelle, the tower and the foundation is established. To evaluate the effect of the soil-structure interaction (SSI) on the dynamic performance of the wind turbine system, a comparative FE model taking the foundation and surrounding soil into consideration is also created. Then, the time history analysis of the system under the input of mean value earthquake record is carried out. The results show that the seismic response of the wind turbine system is remarkable and may be the dominant factor in the design of wind turbine systems located at a seismically active zone. It is also found that apparent difference exists between the results from the model considering SSI effect and that from the model not considering SSI effect.