Abstract: Referring to the structural parameters of NREL offshore wind turbine,a three-dimensional finite element model of offshore wind turbine supported by pile-bucket composite foundation in clay is established based on ABAQUS software platform. The non-linear kinematic hardening model in the form of total stress is used to describe the undrained dynamic stress-strain response of clay. The random wind loads and wave loads are simulated by compiling MATLAB program. The time-domain overall dynamic response analysis of offshore wind turbine supported by pile-bucket composite foundation under earthquake,wind,wave and current loads is carried out,and then the bearing mechanism of pile-bucket composite foundation is revealed. The influence of seismic intensity,soil strength and foundation size on the dynamic response of pile-bucket composite foundation is analyzed. The research results can provide guidance for the seismic design of pile-bucket composite foundation for offshore wind turbine in clay.