Predictive Function Control(PFC) shares the same working principle with traditional predictive control methods,namely model prediction,rolling optimization and feedback compensation.Yet the PFC overmatches traditional ones in its simple algorithm,low computational burden,fast tracking and high precision,which makes it suitable to fast systems,such as excitation system of synchronous generator.This paper introduces the basic principles and characteristics of PFC and applies it to the synchronous generator excitation system.Simulation results show that the PFC can control the synchronous generator's port voltage,short circuit voltage and open circuit voltage,and the control effect of PFC is better than that of PID and FOPID.