Abstract: Three groups of test steels with different rare earth Ce contents were designed to study the effect of rare earth addition on the microstructure, mechanical properties and corrosion resistance of bridge steel. The results show that when the rare earth Ce content is 0.0025 wt%, the distribution of ferrite microstructure and pearlite microstructure is more diffuse and uniform. The test steel has good mechanical properties when the rare earth Ce content is 0.0025 wt%. The yield strength is increased by 14.42%, tensile strength by 7.21%, elongation at break by 7.34%, and hardness by 18.00% and the i MPact performance is the best coMPared with the test steel without added rare earths. The test steel with a rare earth mass fraction of 0.0025 wt% has the best corrosion resistance and the smallest corrosion rate, and the addition of rare earths result in a gradual increase of α-FeOOH and a constant decrease of γ-FeOOH in the corrosion products.