This study investigates the microbiologically influenced corrosion (MIC) of X80 steel accelerated by the phototrophic bacterium Rhodopseudomonas palustris TIE-1. The photorespiration plays a key role in promoting extracellular electron transfer (EET)-induced MIC. In the early corrosion stage, unstable localized corrosion dominated in the dark, while intense diffusion-controlled corrosion occurs in light. Compared to the sterile anaerobic medium, R. palustris TIE-1 accelerated corrosion of X80 steel, with a significantly higher corrosion rate under light conditions, approximately three times that of dark conditions. Inhibition of photosynthetic electron transfer or cessation of photostimulation resulted in pronounced reduction in the corrosion rate.