The invention discloses a method for extracting the backbone topology of a power grid. The method comprises the following steps of: receiving a description about a topology substructure meeting the requirements of a user and a description about the backbone topology substructure extracted from the topology substructure; generating a first incidence matrix on the basis of the description about the topology substructure, and generating a second incidence matrix on the basis of the description about the backbone topology substructure; generating a third incidence matrix according to the bottom-layer topology structure of the power grid; searching for a sub-matrix matched with the first incidence matrix from the third incidence matrix; converting the matched sub-matrix by utilizing the second incidence matrix to obtain a fourth incidence matrix; and generating the backbone topology structure corresponding to the bottom-layer topology structure according to the fourth incidence matrix.