Nowadays online learning is growing strongly, with many diverse options. Learners can utilize electronic devices and internet platforms for studying, searching for materials, and looking up knowledge. In this study, a method for design a knowledge chatbot system in education is proposed. This method includes a knowledge base, which is a knowledge model integrating ontology of relations and operators and knowledge graph, and the algorithms for solving problems on intellectual querying. The proposed method is utilized to build an intelligent chatbot system in the course of Foudation of Database. This chatbot can assist the online learning by querying subject knowledge content, categorizing concepts, and providing support for various types of exercises in the subject. The experimental results show that the built system meets the requirements of an intelligent educational system and outperforms than currently GenAI systems.