This paper discusses the stability issues of rotor speed for floating offshore wind turbine (FOWT) operating in above rated wind speed region. A torque compensator is presented to improve the system stability. As revealed by stability analysis, the bandwidth of blade pitch controller can significantly affect the system stability by introducing the phenomenon of Hopf bifurcation. The proposed compensator contains a proportional controller in the torque control loop, which is derived based on the feedback of the platform pitch angular velocity. With this compensator, the Hopf bifurcation is eliminated and the stability of the FOWT is improved. Simulation results verify the theoretical analysis and control performance of the proposed strategy.