Optical fiber current sensors based on Faraday effect have a lot of advantages over conventional current sensors and have been studied extensively. The structure of Sagnac optical current sensors are developed on the structure of interferometric fiber-optic gyroscope. The external vibration is one of the most important limitations of Sagnac optical current sensors. To eliminate the effect of vibration, a new scheme is given out. The basic principle of the scheme is that there is an extra closed loop to compensate the vibration effect received by the sensing head. Then the polarization states of the lights spreading in the new scheme are analyzed with Jones matrix. The theoretical analysis and the result of the experiment both show that the novel structure of the optical current sensor could completely eliminate the vibration effect in the environment. It is useful to the high accuracy of Sagnac optical current sensor.