The invention discloses a method for setting parameters of an SVC (supplementary damping controller), and belongs to the technical field of power system control. The method comprises the steps of introducing a susceptance variable capacitor; obtaining a transfer function associated with a large power grid by using a test signal method and deducing an open-loop transfer function between an output signal injection point of the supplementary damping controller and an input signal according to an SVC model; and finally calculating the parameters of the supplementary damping controller through a root-locus method. The SVC model is not needed to provide an interface of adding small signal excitation, the application range is wider, simulation and calculation of the test signal method do not need to be carried out again when the parameters of the SVC model change, and the parameters of the supplementary damping controller can be more simply and conveniently obtained.