Knowledge graph is a way to present knowledge relations using graphics, which includes two factors, nodes and edges, and can visualize and visualize all concepts and connections between multiple entities in real life. With the advantages of clear expression, flexible structure adjustment and high efficiency, knowledge graphs play an important value for explainable artificial intelligence. The theoretical content and application of knowledge graphs have been rapidly developed by high-tech means such as big data and machine learning, and the improvement of technology has helped knowledge graphs gain more attention in various fields and produce many research results. In this paper, the author focuses on the research of medical knowledge graphs and analyzes the research of scholars in detail.