The utility model discloses a system for detecting a rod position of a nuclear power plant, which comprises a position detecting device and a control rod group located in a pressure container; the position detecting device is installed on the outer surface of a stroke cover; the position detecting device is connected with the control rod group by a control rod driving mechanism, wherein the position detecting device comprises a plurality of continuous control units; each control unit comprises sensor coils and rod dropping test coils; the plurality of sensor coils are driven by one transformer T1; and the rod dropping testing coils of each control unit are connected from the head to tail to form two leading ends for testing induced voltage. The system for detecting a rod position of a nuclear power plant provided by the utility model is provided with rod dropping test coils. The rod dropping time curve can be acquired by the voltage induced from the rod dropping test coils in the rapid dropping process of control rod. Therefore, the free rod dropping time can be tested conveniently and the test reliability is further improved.