The work aims to explore the corrosion process of sulfate-reducing bacteria by simulating the corrosion of X80 pipeline steel under the action of sulfate-reducing bacteria. Growth curves of sessile SRB and planktonic SRB as well as the pH change curves in solution were obtained through bacterial culture experiment. The electrochemical test was carried out to study the effect of SRB on X80 corrosion. Through immersion experiment, the effect of SRB on corrosion rate was obtained. The surface morphology and the maximum pitting depth after SRB corrosion were analyzed by SEM and laser confocal microscope. The components of the corrosion products were analyzed by EDS and XPS. In the solution inoculated with SRB, there were more sessile SRB fixed on the surface of X80 steel than planktonic SRB. With the growth of culture time, the pH of solution increased. In SRB inoculated environment, the impedance and linear polarization resistance of X80 steel were lower than that of sterile environment, but the corrosion current density was higher than that of sterile environment. With the increase of immersion time, the maximum pitting depth became deeper. According to EDS energy spectrum, the content of S element and O element in the environment containing SRB was higher than that in the sterile environment. XPS results showed that the corrosion products in the environment containing SRB were mostly Fe sulfide. Sessile SRB dissolves iron on the surface of the sample into iron ions and under the action of SRB’s life activities, iron ions react with sulfate ions in the solution to form iron sulfide, thus promoting the corrosion of X80 steel.