Although traditional PID controller is generally used for voltage regulation control in the three-stage AC power generation system, this control strategy cannot meet the requirements of high precision and fast response of complex system in some cases. Based on the analysis on the shortcomings of traditional PID controller, the fuzzy PID control strategy is introduced. There is a problem that the domain of fuzzy PID is too small in the process of dynamic regulation of the system. In order to solve this problem, a PID controller based on the theory of variable universe fuzzy control is proposed. It is compared with the traditional double-loop PID controller and the common fuzzy PID controller on MATLAB/Simulink platform. Simulation results show that the proposed control strategy has better steady-state regulation accuracy and dynamic regulation performance. Compared with the traditional double-loop PID controller, the steady-state error is improved from 0.5% to 0.3%, and the dynamic regulation time is shortened from 0.4 s to 0.2 s.