Objective in order to improve the performance of ultra high strength steel in marine atmospheric corrosion. Methods the microstructure and inclusion morphology of low alloy high strength steel were observed by means of optical microscope and scanning electron microscope. The effects of re on Microstructure and inclusion were analyzed by means of the method of weight loss and electrochemical impedance. Results the rare earth in the low alloy high strength steel has the effect of refining microstructure and modified inclusion. The corrosion resistance of low alloy high strength steel is improved obviously, and the corrosion resistance of the alloy increases with the increase of the content of rare earth. After 384 hours of corrosion, the corrosion weight loss of the low alloy high strength steel with the rare earth content of 0.08% was reduced by 11.4% compared with that of the low alloy high strength steel. Conclusion adding rare earth elements in low alloy high strength steel can refine the microstructure and metamorphic inclusion. Inclusion of rare earth low alloy high strength steel is mainly spherical. The corrosion resistance of low alloy high strength steel with rare earth content of 0.08% is the best.