To investigate the microbiologically influenced corrosion behavior of pipeline steel under the combined action of high pressure and high chloride ion (Cl-) concentration, this study conducted high-pressure immersion experiments containing sulfate-reducing bacteria (SRB) on hot-rolled antibacterial steel, quenched and tempered antibacterial steel, and conventional steel. Corrosion rates, corrosion products, and corrosion morphology were systematically analyzed and compared. The results indicate that high pressure and high Cl- concentration are the primary environmental factors promoting concurrent uniform corrosion and localized pitting. All three steels exhibited the highest corrosion severity under the most severe conditions. The quenched and tempered antibacterial steel consistently maintained the lowest average corrosion rate and controlled pitting depth across various conditions. The corrosion behavior of the hot-rolled antibacterial steel was influenced by the integrity of its product film and biofilm, while the conventional steel was more susceptible to severe localized corrosion under high pressure. Microscopic analysis revealed that the characteristics of corrosion products and biofilm structure jointly determine the differences in corrosion resistance.