Abstract: In order to improve the operational reliability of the instrumentation and control system in nuclear power plants, this article selects the main feedwater pump system of Units 1 and 2 in a certain nuclear power plant as the object, clarifies the problems in logical design and operational functions through reliability analysis, and elaborates on corresponding optimization and improvement methods. The results show that the improved main feedwater pump system meets production control requirements, significantly improves operational stability, and can reduce personnel monitoring workload.