To solve the problems of traditional reporting system, such as difficult manipulation, high levels of data coupling, this paper presents an ontology-based semantic reporting system. It builds a semantic layer between report designer and data source, where enterprise professional information, relevant operties and metadata about data source are described in ontology language. On the report designer interface, semantic information that saved in ontology library is shown and can be dragged to design the report. Ontology-based semantic layer greatly improves design efficiency and makes manipulation easy, because it seals the technical details of data source.