Abstract: The corrosion pit on the steel surface was considered as the semi-ellipsoid based on its characteristics, and the corrosion loss rate was introduced as a damage parameter, then the elastic model of the steel corrosion damage was established by using the damage micromechanics and self-consistent method. The corrosion loss rate, elastic modulus and yield strength of Q235 steel for various corrosion periods was obtained by the indoor salt spray accelerated test and uniaxial tensile test and compared with the simulation values from the elastic model. The results show that early critical point of corrosion rate reduced the damage of corrosion on structural steel significantly; the experiment value was consistent with the theoretical calculation value, indicating the excellent feasibility and accuracy of the established theoretical model.