This paper experimentally investigates the mechanical properties of high-performance steel (690 MPa) under different corrosion degrees. The tensile specimens are examined by indoor salt spray accelerated corrosion tests with varying durations. Tensile tests are performed on the corroded specimens to obtain the corrosion kinetics (corrosion rate) model and residual mechanical properties under different degrees of corrosion, and the correlations between residual mechanical properties and corrosion weight loss rate are discussed. In addition, the paper will adopt Q235 steel as the control to compare the difference in corrosion characteristics between conventional-strength steel and the new high-performance steel under the same corrosion conditions and to compare their corrosion kinetics curves. The paper will establish a new constitutive model for high-performance steel and calibrate the relevant parameters. A new constitutive model was proposed based on the modification of Ramberg-Osgood model. On this basis, the paper will obtain a prediction expression of constitutive parameters considering the degree of corrosion damage. It is found that that the proposed corrosion model is suitable for the new high-performance steel under atmospheric corrosion.