Effects　of　antibacterial　aging　treatment　on　the　corrosion　resistance　of　copper-bearing　duplex　stainless　steels　were　investigated　by　electrochemical　methods.　The　film-cover　method　was　used　to　test　the　antibacterial　effect　of　the　materials.　The　polarization　curve　test　results　show　Ε-Cu　and　other　copper-rich　phases　become　the　weak　point　of　the　passive　film　on　the　surface　of　the　duplex　stainless　steel,　and　the　sites　where　the　coarse　copper-rich　phases　are　precipitated　from　the　matrix　are　apt　to　become　pitting　nucleation　source.　The　proportion　of　coarse　copper-rich　phase　increases,　which　makes　pitting　resistance　of　the　materials　worse.　EIS　test　reveals　that　the　presence　of　Ε-Cu　and　other　copper-rich　phases　in　passive　film　reduces　the　overall　potential　and　passive　film　resistance,　decreasing　the　stability　of　passive　film.　DL-EPR　tests　show　that　Ε-Cu　and　other　copper-rich　phases　in　grain　boundary　makes　it　take　on　anode　characteristic　in　corrosion　process,　leading　to　selectively　intergranular　corrosion.　Compared　with　austenite,　the　intergranular　corrosion　resistance　of　ferrite　decreases　seriously　because　the　copper-rich　phases　are　mainly　precipitated　from　ferrite　matrix.　Antibacterial　tests　show　that　the　microstructure　and　volume　fraction　of　copper-rich　phases　are　the　key　factors　affecting　the　antibacterial　properties　of　the　materials.　Ε-Cu　displays　the　best　antibacterial　effect,　followed　by　metastable　copper-rich　phase,　solid　solution　copper　is　the　worst.　The　more　Ε-Cu　phases　are,　the　more　antibacterial　effect　is.　©　Copyright.