Considering　the　operational　and　parked　states,　a　generalized　single　degree　of　freedom　model　was　established　to　explore　the　influence　mechanism　of　wind-wave　loadings　on　the　seismic　response　of　offshore　wind　turbines　(OWTs).　The　statistical　relationship　between　the　wind　and　wave　was　employed　to　determine　the　parameters　of　the　power　spectra　of　the　wave.　Subsequently,　the　seismic　response　of　the　NREL　5MW　OWT　was　analyzed　using　FAST　to　validate　the　conclusions　of　the　preliminary　analysis　and　evaluate　the　effects　of　wind-wave　loadings　on　the　seismic　response　of　OWTs.　The　results　reveal　that　the　aerodynamic　damping　and　dynamic　loading　effects　of　the　wind　and　wave　had　a　significant　influence　on　the　seismic　response　of　OWTs.　For　wind　turbines　in　the　operational　state,　the　support　structure　is　the　most　dangerous　when　the　mean　wind　speed　of　hub-height　equals　to　the　rated　speed.　In　addition,　the　wind-wave　loadings　reduce　the　internal　force　of　the　mudline　and　tower-top　displacement　under　the　excitation　of　strong　earthquakes.　However,　they　increase　the　internal　forces　and　displacement　amplitudes　at　these　locations　while　the　OWT　is　excited　by　a　weak　earthquake.　Copyright　©2020　Engineering　Mechanics.　All　rights　reserved.