The invention is suitable for an online digital state detection and monitoring technology of electric equipment, meanwhile belongs to the technical field of a million kilowatt nuclear power station, and provides a nuclear power station relay detection method. The method includes the following steps: conducting detection according to state of the nuclear power station relay, wherein the states of the relay can be a state before preparing a part, a state before usage, a state during operation, a failure state and an aging state. According to detected result, the relay is processed. The nuclear power station relay detection method conducts detection of the relay of different states, estimates reliability of the relay, lowers risks of trip and outage of a unit, and improves safety and reliability of operation of the nuclear power station.