The corrosion behavior of corrosion resistant steel(CRS) in a simulated wet–dry acid humid environment was investigated and compared with carbon steel(CS) using corrosion loss, polarization curves, X-ray diffraction(XRD), scanning electron microscopy(SEM), electron probe micro-analysis(EPMA), N_2 adsorption, and X-ray photoelectron spectroscopy(XPS). The results show that the corrosion kinetics of both steels were closely related to the composition and compactness of the rust, and the electrochemical properties of rusted steel. Small amounts of Cu, Cr, and Ni in CRS increased the amount of amorphous phases and decreased the content of γ-Fe OOH in the rust, resulting in higher compactness and electrochemical stability of the CRS rust. The elements Cu, Cr, and Ni were uniformly distributed in the CRS rust and formed CuFeO_2, Cu_2O, CrOOH, NiFe_2O_4, and Ni_2O_3, which enhanced the corrosion resistance of CRS in the wet–dry acid humid environment. The corrosion behavior of corrosion resistant steel (CRS) in a simulated wet-dry acid humid environment was investigated and compared with carbon steel (CS) using corrosion loss, polarization curves, X-ray diffraction (XRD) , electron probe micro-analysis (EPMA), N_2 adsorption, and X-ray photoelectron spectroscopy (XPS). The results show that the corrosion kinetics of both steels were closely related to the composition and compactness of the rust, and the electrochemical properties of Small amounts of Cu, Cr, and Ni in CRS increased the amount of amorphous phases and decreased the content of γ-Fe OOH in the rust, resulting in higher compactness and electrochemical stability of the CRS rust. The elements Cu, Cr , and Ni were uniformly distributed in the CRS rust and formed CuFeO 2, Cu 2 O, CrOOH, NiFe 2 O 4, and Ni 2 O 3, which enhanced the corrosion resistance of CRS in the wet-dry acid humid environment.