Abstract: In order to improve the corrosion resistance of marine duplex stainless steel in sea water environment, the HDR duplex stainless steel is treated by the solid solution and aging treatment, and the 3D microscope, Vickers hardness tester, scanning electron microscope, energy spectrometer and other instruments are used to analyze the microstructure, chemical compositions, hardness, and corrosion resistance. The corrosion resistance of the steel in 3.5% NaCl solution is studied, and the most suitable solution temperature determined. The results show that σphase is precipitated when the specimen is aged when the solid solution temperature is between 1 050 and 1 150 ℃ and the hardness of the specimen is promoted. When the solid solution temperature is 1 100 ℃, the specimen exhibits best pitting corrosion resistance. When the solid solution temperature is between 1 050 and 1 150℃, the aging treatment weakens the corrosion resistance of HDR duplex stainless steel.