In this paper,a dynamic model of the multi-body system of a 1.5MW direct-drive wind turbine is established with the finite element software ANSYS.Then,the natural frequency of the wind turbine is calculated,and the resonance and the stability of the system are analyzed.Moreover,the transient response of each component of the system under extreme operation gusts is discussed.The results indicate that,the tower is flexible;the system is stable and safe at normal working rotational velocity;and that,due to the difference in stiffness of the components,the variation of the tip of the wind turbine blade,which is induced by the coupling of the elastic deformations of three blades and the tower under wind loading,is more complex than that of other components.The flexible structure of the plant trunk is applied to the design of the wind turbine tower,and the feasibility of this bionic design is finally proved.