The normal operation control system performs the operation monitoring, display, control and alarm functions of the new nuclear power plant to maintain the new nuclear power plant system and parameters within the normal operating range, prevent or correct deviations from the normal operating conditions, so as to ensure its continuous operation conditions, so as to ensure its continuous and stable operation and reduce unnecessary shutdown. For new nuclear power plant, it is very important to design a normal operation control system with simple structure, high integration and high reliability. Based on the theory of system engineering, this paper develops a requirement analysis process suitable for the normal operation control system of a new nuclear power plant, captures the needs of all parties on this basis, and forms the top-level design requirements of the system. At the same time, it introduces the functional requirement analysis process, non-functional requirement analysis elements and design constraint analysis elements based on specific accident scenarios, and then obtains the functional architecture design of the normal operation control system to guide the subsequent detailed design.