The invention relates to a photovoltaic power station equivalent modeling method. The photovoltaic power station equivalent modeling method comprises the steps of building a simulation model of a grid-connected photovoltaic generation unit, including, a transient control module; carrying out a fault simulation experiment for the grid-connected photovoltaic generation unit, obtaining active power response curves in the presence of different voltage drop depths and different time of duration, and storing the active power response curves in the presence of different voltage drop depths and different time of duration into corresponding offline databases; selecting matched offline databases based on the really measured voltage drop depth and time of duration, selecting the active power response curves from the matched offline databases based on the output of the grid-connected photovoltaic generation unit, and clustering and grouping the selected active power response curves based on the active power response similarity when the transient control module is enabled so as to obtain multiple generator set groups; calculating a first equivalent parameter of each generator set group and a second equivalent parameter of a current collection circuit, and building an equivalent model based on the first equivalent parameters and the second equivalent parameter.