Abstract: In order to explore the influence of rotor-nacelle assembly（RNA）operation on tuned mass dampers（TMD）vibration control of offshore wind turbine,this paper designs TMD parameters using the first-order frequency fixed-point theory,based on the wind-wavecurrent-RNA operation coupled offshore wind turbine analysis model. Combined with the time-varying vibration characteristics of the wind turbine under the RNA control strategy,the control mechanism of TMD for the for-aft and side-side dynamic responses of the tower top was studied respectively. The results show that TMD cannot effectively control the for-aft vibration,but can significantly suppress the side-side vibration response of the tower top,due to the different dynamic conditions between the for-aft and side-side directions.