Abstract: Before the extended operation of the nuclear power plant, due to the lack of specific understanding of the impact of transient supervision and management on the extended life of the nuclear power plant, the relevant transient supervision and control are only within the design life and do not involve the extended operation. This leads to the failure of the nuclear power plant to manage the consumption of bottleneck transients in the early stage of operation, thus reducing the actual life length of the nuclear power plant; Or the relevant transient data collection is not detailed enough to support more detailed fatigue analysis. In the extended operation evaluation, only more envelope processing can be adopted, which is difficult to achieve a longer evaluation life. In view of the above problems, by learning from the transient related experience in the extended operation research of Qinshan Nuclear Power Plant, this paper studies the transient supervision and data processing of the extended operation of nuclear power plant from the two aspects of daily operation supervision and special continuous evaluation, and forms a transient management technical method suitable for the extended operation of nuclear power plant, which can effectively guide the extended operation of subsequent nuclear power units.