A new electric current sensor based on fiber Bragg grating tuned by magnetostrictive material rod is demonstrated. A fiber Bragg grating is firmly clung on a magnetostrictive rod that is put into the central part of a solenoid. The Bragg wavelength of the fiber grating will shift when the uniform magnetic field in the solenoid changes. The rod will have elastic lengthening along the direction of the magnetic field. The grating resonant wavelength of fiber grating will shift as consequence of the rod lengthening. The relationship between the electric current and the wavelength shift is basically linear. The wavelength range of linear tuning is about 0.9 nm. The electric current range of sensing is about 900 mA. The sensitivity is about 1000 mA/nm. The electric current can be accurate to 10 mA. The experimental result coincides with the theory.