Abstract: Nuclear power operating procedures are the operational procedures that must be followed for the safe operation of nuclear power plants. Having a lot of texts, the operation procedures are inconvenient for users to browse. However, the current electronic procedures have problems such as lack of simplification, weak content relevance, and less superiority than paper procedures. It is imperative to design a simple and efficient electronic procedure system based Ontology model for nuclear power operation. This paper takes the operating procedures of the chemical and volume systems in a nuclear power plant as an example, uses the ontology model theory, analyzes the text of procedures, develops the knowledge of the procedures and extracts key concepts. Using the ontology development tool to build the system, the electronic procedures and visualization are realized. This construction method is also applicable to the operating procedures of other systems, which not only enables the reuse and sharing of ontology knowledge, but also facilitates querying, understanding, and memorizing procedures. It can help the operators in nuclear power plants to use procedures, thereby improving the efficiency and enhancing the safety and intelligence of nuclear power plants.