At present, in some of the domestic thermal power plants, there are some problems such as large deviation between bus voltage and reactive power conversion, unreasonable pulse width adjustment time, reactive power control and excitation control being uncoordinated, etc., affecting the commissioning and qualified rate of thermal power plant automatic voltage control system. In order to solve the above problems, combined with the design features of automatic voltage control system of a thermal power plant in Yunnan province, this paper establishes a stand-alone automatic voltage control system model for the plant. In order to improve the dynamic adjustment performance index and the control effect, a control strategy combining human-simulated intelligent voltage controller and humanoid intelligent reactive power controller is proposed to replace the voltage PID control and unit reactive power nonlinear control on spot. The simulation proves the superiority of the control strategy, realizing the optimization of the automatic voltage control system of the thermal power plant.