Abstract: 5-series aluminum alloys play an important role in many aluminum alloy's due to their excellent comprehensive performance. However, continuous precipitation of Al₃Mg₂ phase at grain boundaries in 5-series aluminum alloys can lead to intergranular corrosion or stress corrosion, thereby degrading mechanical/electrical properties. On the basis of self-developed 5052-Er aluminum alloy, the corrosion resistances of 5052-Er and 5052 aluminum alloy were compared by soaking experiment with 0.2%NaHSO₃ solution. Based on tensile test and conductivity change, the quantitative law of mechanical and electrical properties attenuation of 5052-Er under different corrosion time were discussed, and the internal reasons of performance attenuation were analyzed by the analysis of the changes of microstruture and structure before and after soaking. The results show that after 144 h immersion, the corrosion mass loss of 5052-Er is about 62.3% that of 5052. Before soaking, the tensile strength of 5052-Er alloy is 15.9% higher than that of 5052 alloy, and its tensile strength remains basically unchanged after 144 h of soaking. Before soaking, the conductivity of 5052-Er is 28.4% higher than that of 5052 alloy; after 144 h immersion, its conductivity is 37.7% higher than that of 5052 alloy. The addition of Er improves the corrosion resistance of 5052 aluminum alloy in the simulated industrial environment, and has the effect of fine-grain strengthening and second- phase strengthening, which enhances the mechanical and electrical properties of the material.