Knowledge graph technology is used increasingly widely in industries. Therefore, it is more important to study its application in the field of geological reports to realize accurate queries and visualization for library users. Taking geological reports as the research object, this study uses crawler technology to obtain mineral, geographic area, organization and other entity information in geological reports. With the help of related technologies of knowledge graph, the study designs geological entities and relations for the knowledge graph of geological reports. After named entity recognition, relation extraction and attribute extraction, 266787 geological report entities and 306686 relations are constructed. Knowledge graphs are stored in the Neo4j graph database to improve the performance of geological data query and facilitate the query of library users. This research can provide theoretical support for the application of the knowledge graph to geological reports.