The invention discloses a method and a device for controlling a high-excitation-multiple magnetic control high-voltage shunt reactor. The method specifically comprises the steps: (1) variable-parameter PID closed-loop control is adopted for the adjustment of system voltage and reactive power, independent PID calculation is carried out on the deviation between a reference value and a measured value, and U is output through a control mode selection module; U is output after the deviation between a maximum exciting current control set value and an instantaneous exciting current valueis subjected to a PI operation link; and U and U are added together, and a final excitation control voltage U is generated through amplification and amplitude limiting; (2) variable parameter PID calculation is adopted for PID closed-loop control over system voltage and reactive power, and proportion, integration and differential parameters are dynamically adjusted according to thedeviation value of a control target; and (3) parameter adjustment and effect confirmation are carried out on site by adopting a reference value step test method. According to the invention, an excitation system has high-excitation-multiple quick response and steady-state stable adjustment capabilities in a safe operation range, the high-excitation-voltage strong excitation multiple effect of the excitation system can be fully exerted, and the quick response capability of the system can be improved.