Abstract: In recent years, multiple nuclear power units in China have experienced increasingly frequent power outages, including a large number of newly commissioned units that also experience power outages in the first few fuel cycles. This poses great challenges to daily monitoring and diagnosis of power outages. Based on the common problems in the current power plant output supervision work, combined with the operating characteristics of nuclear power turbine generator units, the optimization of the output supervision and diagnosis methods and criteria for turbine generator units has greatly improved the efficiency of nuclear power turbine generator unit output supervision and the accuracy of diagnosis, ensuring the efficient operation of nuclear power units.