The　development　of　pitting　corrosion　on　L245　carbon　steel　in　a　culture　medium　solution　containing　sulfate-reducing　bacteria　(SRB)　was　investigated.　The　results　showed　that　the　occurrence　of　corrosion　in　L245　carbon　steel　is　closely　linked　to　the　evolution　of　biofilm　and　product　film.　As　the　test　duration　extended,　overall　corrosion　was　inhibited.　Simultaneously,　bacteria　beneath　the　film　layer　promoted　the　generation　and　development　of　pitting　corrosion,　and　the　aggregation　of　bacteria　(colonies)　led　to　the　aggregation　of　pitting　corrosion.