The invention discloses a detecting system for locating the leakage of a nuclear power station. The detecting system comprises a power supply, a first multi-core wire electrically connected with one pole of the power supply, a second multi-core wire electrically connected with the other pole of the power supply, a plurality of first conductive wires electrically connected with multiple core wiresin the first multi-core wire in a one-to-one corresponding mode, and a plurality of second conductive wires electrically connected with multiple core wires in the second multi-core wire in a one-to-one corresponding mode. The first conductive wires and the second conductive wires are interwoven into a mesh-shaped structure. All intersecting point positions of the first conductive wires and the second conductive wires are each wrapped by a thermal sensitive insulation material. The detecting system further comprises a plurality of prompting modules connected with the core wires of the first multi-core wire or the second multi-core wire in a one-to-one corresponding mode. When a current circuit is formed by the core wires, the prompting module corresponding to the current circuit sends out aprompting signal. Due to the settings, the detecting system is simple in structure and high in reliability and can precisely detect the high-temperature medium leakage position.