Abstract: Additive manufacturing, owning to its excellent design freedom and extremely high material utilization, has become a key strategy to produce complex alloy steels. However, the non-equilibrium solidification characteristics （rapid cooling rate and strong temperature gradients）, induces metallurgical defects and residual stress, which severely impacts the density and compositional uniformity of the components. Poor quality adversely affects the corrosion resistance of additive manufacturing alloy steel. This paper systematically reviews the characteristics of metal additive manufacturing and summarizes research progress related delaying corrosion process via process parameter optimization, chemical composition design, and heat treatment control to improve porosity, microstructure, and residual stress. Different process parameters directly influence the metallurgical defects. The porosity defects are avoided by adjusting process parameters, which improve pitting corrosion resistance of alloy steels. Introducing nitrogen, chromium, copper, and rare earth elements through in-situ alloying regulates corrosion product and enhances passivation film stability, thereby delaying corrosion process and improving corrosion resistance. Heat treatment improves microstructure and releases residual stresses, further enhancing corrosion resistance by promoting compositional uniformity and controlling carbide distribution. In this paper, the core challenges in the corrosion resistant of additive manufacturing alloy steels are pointed out. The relationships among "process-composition-microstructure-property" should be clarified. The multi-scale databases and standardized evaluation criteria should be established. This paper provides theoretical foundations and design guidance for developing additive manufacturing alloy steels with excellent corrosion resistant.