A method and device for optimal power flow calculation in power systems based on generalized Nash equilibrium are disclosed. The method comprises: determining first optimal power flow model corresponding to distribution network and second optimal power flow model corresponding to each microgrid; constructing a third optimal power flow model based on the first optimal power flow model, each second optimal power flow model and boundary coupling constraint condition; determining generalized Nash equilibrium solution corresponding to the third optimal power flow model; determining generalized Nash equilibrium constraint condition corresponding to collaborative objective function and the Nash equilibrium solution; determining fourth optimal power flow model corresponding to the collaborative objective function, with constraint condition including the generalized Nash equilibrium constraint condition; determining Pareto optimal solution corresponding to the fourth optimal power flow model to determine an optimal power flow. Accordingly, effectiveness of optimization management is improved.