The invention discloses a DCS for a nuclear power station. The DCS comprises a plurality of DO modules for sending digital quantity signals in an instrument control system to an onsite instrument, and a power supply device for supplying power to the DO modules. The power output end of the power supply device is connected with a bus, and each DO module is connected with the bus through a fuse terminal so as to obtain power; and the DCS system further comprises a monitoring alarm device for monitoring whether power failure occurs in the DO modules and emitting alarm signals when the power failure occurs in the DO modules. The DCS for the nuclear power station can be used for monitoring whether the power failure occurs in the DO modules and emitting the alarm signals when the power failure occurs in the DO modules, such that the monitoring defect of a conventional DCS is improved, the stability and reliability of the DCS for the nuclear power station are ensured, the probabilities of power station tripping and reactor shutdown caused by incapability of controlling field equipment due to loss of a driving power supply are greatly reduced, the equipment utilization rate is effectively improved, the equipment utilization economic benefits are enhanced, and the risks of equipment damage and personal damage are reduced.