The invention belongs to the field of an electrical power system and the automation technology thereof, and discloses a power grid frequency simulation parameter identification method based on a simplex method. The method comprises the following steps of: firstly, utilizing a multi-parameter sensitivity analysis method to determine a simulation parameter group to be identified; then, utilizing a simplex algorithm based on a numerical analysis method to intelligently guide a parameter optimizing direction; and utilizing the simulation result of the electromechanical transient simulation program BPA (Bonneville Power Administration) of the electrical power system to calculate a target function value so as to quickly and reliably search an optimal parameter combination. By use of the method, one set of parameters which enable the simulation result to have a smallest error compared with a practical response result can be identified, the accuracy of power grid frequency simulation in the future is improved, simulation time consumption can be shortened, and the optimization efficiency of the parameter identification can be greatly improved.