Abstract: In order to evaluate the performance of an aluminum conductor steel reinforced (ACSR) that had served in a coastal chemical plant area for 30 years, a series of analyses and tests were conducted using metallographic microscope, scanning electron microscope, energy spectrometer, electronic universal material tester, and digital bridge tester, respectively. These investigations focused on the macroscopic and microscopic structure, micro area composition, tensile strength and volume resistivity of the wires to assess whether the performance of the conductor meets the service requirements. The results show that the outer aluminum wires of the conductor have been severely corroded, leading to a significantly reduction in tensile strength, and failure to meet standard requirements for volume resistivity. The intermediate and inner aluminum wires have been slightly corroded, but their performance has no significant deterioration. The steel wires shows significant corrosion,with the local zinc layer completely corroded, which significantly reducing the mechanical properties of the material. The direct current resistance and the combined breaking force of the conductor have significantly deteriorated at 20 ℃ and can no longer meet the service requirements. It is recommended to replace the corrosion-resistant conductors, such as corrosion-resistant aluminum clad ACSR, as soon as possible according to the service environment.