Aiming at the problems of single original drawing information and low digitization of secondary system of substation, the activation technology of secondary drawing of substation based on the theory of atlas is proposed. This method topologies the electrical elements, establishes the Laplace matrix of the elements to represent the structural features of the diagram, realizes the matching and recognition of the elements by the similarity matrix algorithm, and realizes the elements by the breadth first search algorithm The part connection relation is extracted to determine the component features, circuit attributes and logical connection of the secondary drawing. Taking the application of on-line monitoring and diagnosis, model file aided design and simulation training as examples, this paper discusses in detail the application practice of activation drawing of secondary system in operation and maintenance, and further proves the innovation and effectiveness of this method.