With the rapid development of electricity and transport industry, more and more buried pipelines are parallel or cross to the high voltage transmission line and the electrified railway. In this work, microbiological analysis method was used to investigate the effect of alternating current (AC) on the physiology of sulfate reducing bacteria (SRB). Electrochemical methods, including open circuit potential, potentiondynamic polarization curves and electrochemical impedance spectroscopy (EIS) on Q235 steel samples, were performed in soil leaching solution to study the electrochemical behavior with the presence or absence of AC and SRB. The corrosion morphology was observed by scanning electron microscopy (SEM). The results indicate that the AC which current density is 50 A/m² and frequency is 50 Hz has only a small impact on the growth of SRB, but its alternating electric field can reduce the adsorption and promote the desorption of the biofilm. During the initial experiment, the active biofilm can inhibit the corrosion of Q235 steel due to the electronegativity and the physical barrier, but the microbial metabolites would promote the corrosion during the later experiment without active biofilm. AC can improve the corrosion rate and lead the corrosion products loose because of the rectifying effect, the alternating electric field and the self catalytic effect of pitting corrosion.