High-manganese damping steel has shown broad application prospects in fields such as bridges, rail transit, and military industry that withstand large vibrations and impacts owing to its high strength, ultralow yield ratio, good damping performance, and excellent economic performance. However, the poor corrosion resistance of high-manganese steel has always been a key factor limiting its rapid development. To address this problem, three corrosion-resistant high-manganese damping steels with different Cu and Ni contents were prepared using vacuum induction melting and two-stage rolling processes. The electrochemical properties, corrosion rate, corrosion morphology, corrosion product phase, and structure of the test materials were characterized and analyzed through atmospheric exposure tests and electrochemical testing and by using scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) methods. The research results show that compared to the high-manganese damping steel added with Cu only, the one added with Cu and Ni exhibited better electrochemical stability. The addition of 1.2 wt.% Cu and 1.0 wt.% Ni to steel resulted in a positive shift in the corrosion potential of approximately 200 mV and a decrease in the corrosion current density by approximately 50%. After the exposure experiment, the high-manganese damping steel added with Cu and Ni also exhibited better corrosion resistance. Compared to the 8Cu and 8Cu5Ni steels, the corrosion rate of 12Cu10Ni decreased by approximately 70%. Based on the distribution of elements in the three types of steel, Fe, O, Mn, Cu, and Ni were uniformly distributed in the corrosion product layer without noticeable enrichment. The main corrosion products of the three types of steel were composed of gamma-FeOOH, alpha-FeOOH, Fe3O4 , Mn3O4 , and manganese iron oxide (MnFe2O4). In the corrosion product layer, Cu and Ni affected the generation of the main corrosion products, on the one hand, and existed in the form of corrosion-resistant products, such as CuO, NiOOH, and NiO, on the other hand. When Cu was added separately to the steel, the ions had sufficient diffusion channels owing to the rapid corrosion of high-manganese steel and the porous corrosion product layer. Therefore, there were fewer Cu products in the corrosion-product layer, and the steel matrix exhibited apparent local corrosion characteristics. The addition of Ni enhanced the formation of corrosion product alpha-FeOOH, thereby improving the stability and density of the corrosion product layer. The addition of Ni also inhibited the doping of Mn into Fe3O4 , resulting in the disappearance of iron-manganese oxides and an overall improvement in the electrochemical stability of the corrosion product layer. As the density of the corrosion-product layer increased, the diffusion of various ions in the steel became difficult, and the Cu oxide content in the corrosion-product layer increased, resulting in uniform corrosion characteristics on the overall surface of the steel. The synergistic addition of higher amounts of Cu and Ni further increased the alpha-FeOOH content. Notably, corrosion resistant products such as NiOOH and CuO within the corrosion products showed a significant enhancement, whereas the contents of MnFe2O4 and Mn2O3 , known for their higher activity, experienced a decrease. The particles of the corrosion product were uniform and small. The overall product layer was dense and smooth, which effectively isolated the erosion of corrosive media and demonstrated excellent protection. The optimization of the synergistic addition of Cu and Ni effectively suppresses the insufficient corrosion resistance of high-manganese steel, providing support data for the design and in-depth research on more corrosion-resistant high-manganese damping steel in the future and a design basis for achieving safe service of high-manganese steel in the atmospheric environment.