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　epsilon-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　epsilon-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　epsilon-Cu　and　other　copper-rich　phases　in　grain　boundary　makes　it　take　on　anode　characteristic　in　corrosion　resistance　of　ferrite　decreases　seriously　because　the　copper-rich　phases　are　mainly　precipitated　form　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.　epsilon-Cu　displays　the　best　antibacterial　effect,　followed　by　metastable　copper-rich　phase,　solid　solution　copper　is　the　worst.　The　more　epsilon-Cu　phases　are,　the　more　antibacterial　effect　is.