The invention relates to the field of electric protection of a nuclear power plant, and discloses a control system capable of locating a fault relay, which comprises a control circuit separately connected with a switch module and peripheral equipment, the control circuit includes a relay for receiving a switch signal output by a switch module and outputting a control signal, the control signal isused to achieve the closing and tripping control of peripheral equipment. The control circuit includes a fault-hold circuit, which is configured to indicate a fault relay in the control circuit when control circuit is used to achieve the closing control of the peripheral equipment. The problem that the fault relay can't be located in a relay-type control board is solved.