Electric power system is likely to emerge chaotic oscillation under stronger periodic load perturbation, even lose stability. The hybrid controller based on direct adaptive fuzzy control and supervision control has been designed to retrain chaotic oscillation when the magnitude of the periodic load perturbation is unknown. First, a direct adaptive fuzzy controller is designed as the main controller. Then, in order to ensure the stability of the closed-loop system, a supervisory controller is designed, which is working only when the fuzzy controller can not stabilize the controlled power system. The stability of the closed-loop control system is proved by Lyapunov stability theory. Finally, simulation results show that the proposed controller can suppress the power system chaotic oscillations, and achieve no static error control.