Experimental setup for current measurement and a novel signal detection method for demodulation of fiber Bragg grating wavelength shift are developed. Being attached respectively on the upper and lower surface of a pendulum-type cantilever element, only a couple of matched FBGs are used for both current sensing and wavelength shift signal demodulating. So, the received light power will change due to the split of the two reflected spectrum of FBGs, which is corresponding to the electromagnetic force caused by the measured current. In addition, cross-sensitivity effect of FBG-based sensor automatically solved due to a differential signal process method. Static and quasistatic measurement results indicate the feasibility of the developed sensor system. Measurement error of