A new electric current sensor based on a fiber Bragg grating tuned by a magnetostrictive material rod was obtained. The fiber Bragg grating was firmly clung on a magnetostrictive rod that was put into the central part of a solenoid. The rod was elastically lengthened along the direction of the magnetic field, so the Bragg wavelength of the fiber Bragg grating was changed when the uniform magnetic field in the solenoid increased. The relationship between the electric current in the solenoid and the change of wavelength is basically linear. The wavelength range of linear tuning is about 0.9nm, and its tuning sensitivity is about 0.001nm/mA.