In existing equivalent models of large-scale wind farms, multi-wind turbines are often aggregated using a multiplier element to save modeling and simulation computing resources. The multiplier element of a single-wind turbine aggregation model of wind farm is widely used in wind farm modeling, but the parameter setting lacks regularity. Thus this paper studies the influence of multiplier element impedance parameters on wind farm equivalent modeling. First, it starts with a multiplier element on the official website of PSCAD to analyze the relationship and importance of each self-defined impedance parameter. Second, a reference test model of a wind farm is built and equivalent aggregation is carried out. Through a parameter traversal test, the influence mechanism of impedance parameters of multiplier elements on equivalent error is studied. From the limitations of steady-state operating point equivalent error and simulation time step, the method of impedance parameter selection of the multiplier element is proposed. Finally, three operating conditions of steady-state operating point, three-phase voltage dip and broadband oscillation are selected to verify the influence mechanism and recommended parameters. Some suggestions are provided for the parameter setting of the impedance of the multiplier element in modeling and simulation of large wind farms in terms of equivalent error.