In this study, the resonant motion of a floating offshore wind system due to negative damping was mitigated by peak shaving algorithms of the NREL ROSCO controller, and the decreased gains of the blade pitch controller by the gain detuning method for the floating system was increased to the gains of onshore baseline controller to improve the power performance of the turbine. To check the performance of the controller, the dynamic responses between the existing gain-detuned pitch controller and the ROSCO controller with peak shaving control for an OC4 floating offshore wind system were compared. As a result of DLC1.1 at near-rated wind speed, when peak shaving was applied, the average generator power decreased by 1.9%, but it was confirmed that the standard deviation was reduced and stability was improved with fast pitch regulation. In addition, since peak shaving reduces the maximum thrust of the rotor, was confirmed that not only are the loads of the blades and tower reduced, but the surge motion of the floater is also reduced, and the tension of the mooring lines is reduced.