Abstract: Knowledge graph (KG) is an emerging knowledge representation method in the field of artificial intelligence technology, and is a hot research topic in the field of knowledge automation. Knowledge graph expresses the relationship between entities through triples, and thus expresses knowledge in the form of "graph". Because the topological structure of power system fits the relation structure of graph theory, it has become the focus of domestic and foreign research to express the hidden knowledge in power system dispatching operation by the way of knowledge graph. In this paper, the existing achievements of knowledge graph are summarized involving the development of artificial intelligence in power system, the application of knowledge graph in various fields, the construction of knowledge graph and the method of knowledge mining, and the further application of knowledge graph in power system is prospected.