In order to effectively suppress the power fluctuations of the offshore floating wind turbine caused by the random wind and wave loads, a pitch active disturbance rejection control (ADRC) strategy was proposed. Considering aerodynamics, hydrodynamics, structure flexibility and pitch control, an aero-elastic-hydro-servo coupling dynamic model for the 5 MW offshore floating wind turbine was established. Pitch ADRC controller was designed based on the target of the constant torque control, in which the bandwidth setting method and BP neural network were used to set controller parameters. The suppression effects of the pitch ADRC on the power fluctuations were analyzed. The results show that the pitch ADRC based on bandwidth tuning and BP neural network tuning can effectively improve the pitch sensitivity and suppress the power fluctuation, and the fluctuation amplitude is reduced compared with the traditional PID control.