The electrode pulsed arc discharge excitation experiments on fiber Bragg grating (FBG) inscribed by ultraviolet exposure are reported. The effect of discharging at different grating positions on the spectral characteristics of fiber grating is studied especially. Experimental results show that the reflectivity of fiber grating is decreased,the grating spectrum is broadened and shows a red shift during electrode discharge excitation. The spectral changes induced by discharge are reversible. The spectral characteristics of fiber grating are analyzed in a non-uniform temperature field formed by electrode discharge with the transfer matrix method, and the theoretical results are in good agreement with the experimental results. Specifically, when the electrode discharges in the center of fiber grating, the decline amplitude of grating reflectivity reaches to maximum and the optical reflection spectrum is 12 dB less than initial spectrum, which shows switching characteristic.