Abstract: The pressure pipeline in the anaerobic pretreatment system of wastewater in a chemical enterprise had penetrating corrosion defects. The cause of corrosion was analyzed by means of macroscopic observation, chemical composition analysis, scanning electron microscopy and energy spectrum analysis, metallographic examination and rapid detection of sulfate reducing bacteria (SRB). The results show that the anaerobic microbial sulfate reducing bacteria that undergo biogas reaction led to the destruction of the passivation film of the stainless steel pipeline, which promoted the corrosion process of the stainless steel and ultimately caused penetrating corrosion defects.