In order to meet the detailed simulation requirements for large-scale wind power integration into regional power grid, an equivalence method applicable to regional power grid integration with wind power is proposed. Unlike traditional dynamic equivalence methods that focus on the main grid, the equivalence of regional power grid with enriching wind power resources must not only examine the characteristics of intensive wind power integration within the regional power grid, delineate the influence scope of each wind farm, but also comprehensively consider the constraints on the source and load characteristics of the external grid at the boundary nodes. The proposed method can simplify the external grid on a large scale while maintaining consistent steady-state and transient characteristics, achieving equivalent modeling of the regional power grid. Firstly, rather than the traditional scheme of equating the grid at the access point of wind farms using short-circuit ratio and other electrical strength indexes, it is proposed to define the study area and the external area to be equated by residual voltage. Then, the regional power grid is further simplified by considering topological constraints of the regional power grid. Additionally, the equivalent model of the external system is constructed by combining an equivalent synchronous generator and composite load at the boundary node. Finally, the proposed method is applied to a practical regional power grid with enriching wind power resources. The effectiveness of the proposed method is verified by the simulation results.