In the current circuit, when the electric energy transmits in wire, the wire will generate heat because of the high current through it, the high temperature will even result in a fire. Therefore, monitoring the current of the wire has important significance for the prevention of the overload and the fire of the wire. Based on the related theories of optical fiber grating temperature measurement, a sensing system for wire load detection is designed. The relationship between the changing of the center wavelength of the fiber grating temperature sensor and the wire load in 0~5 A is researched in experiments, Experimental results show that wire load detection is feasible and provides a new method for real-time monitoring of wire load and the judgment of open and short circuit fault.