The course of “Reinforced concrete structure design principles” has the characteristics of many concepts, contents, symbols and formulas. Therefore, how to effectively study, teach and expand this course has become the key content for the teaching reform of “Reinforced concrete structure design principles”. In this paper, the philosophical concept of ontology and the modeling steps of ontology model are introduced, and the main teaching contents of the course “Reinforced concrete structure design principles” are integrated with ontology. Through the establishment of the refined ontology model for the main teaching contents of the course “Reinforced concrete structure design principles”. It is considered that Bayesian thinking can update and improve people"s understanding of the objective world. Based on the built ontology models of the main teaching content for the course “Reinforced concrete structure design principles”, with the relevant information of the service reinforced concrete components, Bayesian method can be used to expand the built ontology models, which can deepen students’ mastery and understanding for the course contents, improve students’ professional knowledge ability and teachers’ teaching quality, and provide a new teaching method for the related courses of civil engineering.