The integrated fatigue analysis method of Offshore Wind Turbine (OWT) is established based on the tubular joint hot spot Stress Concentration Factor (SCF) calculation module and tubular joint fatigue stress time history calculation module developed by Python and the coupled aero-hydro-elastic numerical model. Taken the OWT designed referring to NREL 5 MW foundation OWT and NREL OC4 jacket foundation substructure, the dynamic structural responses of the OWT under the typical fatigue limit states are analyzed. The influence of the instantaneous initial responses of the coupling analysis model, random seeds in the generation of stochastic environmental conditions and directions of inflow winds and waves on the fatigue of the tubular joints is investigated. According to the performed research, the necessity of the coupled analysis model in the fatigue analysis of OWT is validated.