Abstract: In some cabins inside the hull, oil and sewage are often accumulated at the bottom of the cabin due to the oil leakage of shafting and piping and the domestic sewage not cleaned in time, which provides favorable conditions for the growth and reproduction of corrosive microorganisms. The effect of sulfate-reducing bacteria (SRB), isolated and purified from bilge environment, on the corrosion of the new-type hull low alloy steel is studied by means of fluorescence microscopy, weight loss analysis, electrochemical analysis, corrosion product composition analysis and composition analysis. The results show that in the initial stage of SRB corrosion, extracellular polymer substances (EPS) have a certain inhibitory effect on the overall corrosion. However, with the extension of time, the iron sulfur compound layer can act as the cathode, together with the small anode at the exposed part and the SRB, it can accelerate the dissolution of the anode at the fracture and promote pitting corrosion. Within the 14 days of period, the corrosion current density in the SRB medium is greater than that in the sterilization medium, and the annual average corrosion rate is 1.36 times of that in the sterilization medium.