The corrosion behavior of cupronickel alloy immersed in the simulated seawater in or without the presence of sulfate-reducing bacteria (SRB) was studied.The results of scanning electronic microscopy and electrochemical impedance spectra reveal that corrosion of the sample immersed in the simulated seawater with SRB was more serious than that immersed in the simulated seawater without SRB.The atomic force microscopy images show that after immersion for 15 days,the surface roughness of the sample in the simulated seawater with SRB was higher than that of the sample in the simulated seawater without SRB.The analysis of confocal laser scanning microscopy indicates that the average depth of the pits on the surface of the sample in the simulated seawater with SRB was almost twice deeper than that of the sample inthe simulated seawater without SRB.