Abstract: Caused by the long-term coupling effect of wind and wave, the vibration of offshore wind turbine will affect the power output of the generator unit, aggravate the cumulative fatigue damage of the structure and reduce the safety of the structure. In order to understand the dynamic characteristics of offshore wind turbine more scientifically, this paper uses von Karman wind spectrum model to simulate the turbulent wind field and calculate the aerodynamic load by considering the Rotor–Nacelle Assembly (RNA) operation and the correlation between wind and wave, and calculates the wave load at monopile foundation structure by Morrison equation. The dynamic response of NREL 5MW monopile wind turbine is analyzed, and the dynamic behavior patterns under different states are compared. Through batch processing program, the response of offshore wind turbine with the wind speed range of 3 m/s~30 m/s is calculated, and the variation laws of displacement and acceleration response of offshore wind turbine with wind speed under RNA operation are explored. The results show that the dynamic response of offshore wind turbine under different working conditions has different spectrum characteristics, and the peak response of displacement and acceleration will be amplified by RNA operation.