In　this　study,　a　sophisticated　3D　finite　element　model　of　NREL　5MW　wind　turbine　(WT)　superstructure　is　developed　using　Abaqus,　which　includes　necessary　functional　features,　such　as　rotor　rotation,　drivetrain,　pitch,　servo-control,　etc.　A　multi-step　validation　process　has　been　conducted　in　order　to　verify　the　reliability　of　the　blade,　the　Rotor-Nacelle　Assembly　(RNA)　and　the　entire　WT　model.　In　the　time　domain,　a　software　framework　of　ABA-OWT　is　developed　for　the　dynamic　analysis　of　offshore　wind　turbine　(OWT)　based　on　the　Abaqus　WT　structure　model　and　FAST　submodules.　The　framework　is　capable　of　computing　wind　loads,　wave　loads,　and　servo-control　commands　in　a　fully　coupled　way.　The　pile-soil　interaction　(PSI)　is　modeled　by　nonlinear　p-y,　t-z　and　Q-z　springs　and　the　dashpots　parallel　with　them.　A　typical　sandy　site　is　considered,　while　several　identical　analyses　are　performed　for　both　numerical　models　including　fixed　base　and　PSI.　After　calculating　the　eigenvalues　of　the　WT　structure　and　analyzing　its　dynamic　response　to　the　combined　action　of　wind　and　wave,　three　representative　wind-wave　load　cases　are　chosen　for　subsequent　seismic　response　study.　The　important　conclusions　are　as　follows.　Firstly,　the　PSI　reduces　the　natural　frequencies　of　FA1,　SS1　and　FA2　by　about　12%　and　SS2　by　23.5%.　Secondly,　under　the　combined　action　of　wind　and　wave,　the　PSI　significantly　increases　the　tower-top　peak　motion　responses　in　normal　operating　cases,　but　its　influence　on　the　mudline　peak　internal　force　responses　is　almost　negligible;　For　parking　cases,　the　PSI　dramatically　enlarges　the　peaks　of　the　tower-top　motion　responses　and　the　mudline　bending　moment,　and　the　effect　of　PSI　on　the　structural　peak　responses　in　parking　cases　is　greater　than　that　in　normal　operating　cases.　Finally,　under　the　conjoint　action　of　wind,　wave　and　seismic,　the　PSI　increases　the　tower-top　peak　motion　responses　and　reduce　the　mudline　peak　internal　force　responses,　and　because　of　the　aeroelastic　effects,　the　influence　of　PSI　on　the　structural　peak　responses　in　normal　operating　cases　is　always　the　smallest.　In　a　word,　the　PSI　has　a　remarkable　impact　on　the　natural　frequency,　dynamic　response　and　seismic　response　of　offshore　wind　turbine　(OWT)　with　monopile　foundation,　which　should　be　considered　in　a　reasonable　way　in　the　practical　offshore　wind　power　project.