The CSSCI information services system can only provide single and linear retrieval, and the retrieval effect is not very good. The main reason lies in the unreasonable data organization background. Therefore, the authors put forward the solution which uses knowledge services platform based on Ontology instead of the existing CSSCI information services system, and provide the services in the level of knowledge, so that to improve the retrieval environment. The paper proposes a general model of information retrieval system based on Ontology, designs a practical knowledge services platform named KRSP_CSSCI_Onto, and gives the basic functions and system framework of the platform. An experimental knowledge retrieval system is developed hereby, and the applications of Ontology in knowledge retrieval services is expounded in detail, including semantic extension of search expression, related knowledge recommendation of query results, knowledge navigation based academic resource networks model and knowledge relationships retrieval based rule library.