Effects　of　aging　treatment　at540~580℃　on　the　corrosion　resistance　of　a　copper-bearing　duplex　stainless　were　studied　by　electrochemical　measurement　in　culture　medium　with　and　without　bacteria.　The　surface　morphology　of　the　biofilms　and　the　corrosion　products　formed　on　the　steels　solution　treated　and　aging　treated　at560℃were　characterized　by　OM　and　XPS.　The　results　show　that　in　the　culture　medium　without　bacteria,　but　the　proportion　of　coarse　copper-　rich　phase　in　the　corrosion　products　on　the　aged　steel　increases　with　the　increasing　aging　temperature,　correspondingly　the　corrosion　resistance　of　the　aged　steels　became　worse;　in　comparison　with　those　in　the　culture　medium　without　bacteria,　the　corrosion　resistance　of　the　steels　solution　treated　and　aged　at　540℃　is　inferior,　while　of　the　steels　aged　at　560　and　580℃　is　better　in　the　culture　medium　with　bacteria,　correspondingly　a　thicker　porous　microbiological　biofilm　with　low　CuCO3　content　formed　on　the　steel　solution　treated　in　the　culture　medium　with　bacteria,　which　possessed　less　protectiveness,　while　a　thin　and　dense　biofilm　with　high　CuCO3　content　formed　on　the　steel　aged　at560℃,　which　could　enhance　the　corrosion　resistance　of　the　steel.　©　2014,　Chinese　Society　of　Corrosion　and　Protection.　All　rights　received.