2120　duplex　stainless　steel(DSS)　with　and　without　0.1%　niobium　content　were　prepared　by　investment　casting.　The　pitting　resistance　and　its　influence　law　of　the　steel　in　3.5%　NaCl　solution　at　different　temperatures　were　investigated　by　electrochemical　corrosion　methods　including　potentiodynamic　polarization　curve　test　and　electrochemical　impedance　spectroscopy　test,　combined　with　optical　microscope,　scanning　electron　microscope,　and　energy　spectrum　analysis.　The　results　indicate　that　the　stability　of　surface　passivation　film　of　both　steels　is　decreased　with　the　increase　of　temperature.　Meanwhile,　the　pitting　potential　is　reduced,　while　the　self-corrosion　current　density　is　increased.　The　content　of　α　is　increased　with　niobium-rich　phase　precipitated　in　the　matrix　after　Nb　addition,　and　dimension　of　corrosion　hole　on　the　stainless　steel　surface　is　expanded　with　temperature　increase.　©　2022,　Journal　Office　of　Special　Casting　and　Nonferrous　Alloys.　All　right　reserved.