The invention discloses a serious accident instrument control system for a nuclear power station, comprising an on-site instrument layer, a logic processing layer and an operation and information management system; the on-site instrument layer comprises an on-site instrument and an on-site executing mechanism; the on-site instrument and the on-site executing mechanism can be used for executing functions under serious accident, design basis accident and normal running condition; the logic processing layer collects the information from the on-site instrument layer, and outputs information to the operation and information management system to display; the operation and information management system receives and sends the control order to the logic processing layer, and the logic processing layer outputs the control order to the on-site instrument layer to execute. The serious accident instrument control system for the nuclear power station is supplied by regular power source and specific UPS at the same time. Compared with the prior art, the serious accident instrument control system for the nuclear power station guarantees that the serious accident handling strategy is effectively practiced under the condition of serious accident and lost alternating current of the whole plant, and the safety of the nuclear power station is improved.