The work aims to improve both the appearance and functionality of carbon steel wire, so as to deeply understand the bipolar electrolytic pickling process and its influence on the surface of steel wire. Electrochemical station was used to simulate the bipolar electrolytic pickling process by designing the electrolytic program under different current densities and the electrolytic process was analyzed according to potential curve. The pickled surface of steel wire was characterized via OM, CLSM, SEM and XPS. Fe dissolving occurred firstly during the non-steady anodic processes. The surface could only be passivated rapidly when the current density was up to 816.0 A/dm2, after which the anodic process was further polarized so that oxygen evolution occurred. The pickling under extremely low current density (54.4 A/dm2) resulted in shining surface. The pickling under high current density (163.2~272.0 A/dm2) resulted in a dark and oxidized surface, but with special lamella surface morphology. The pickling under higher current density of 544.0 A/dm2 corroded the surface of steel wire which was nearly broken, but a shining surface together with lamella morphology could be obtained under extremely high current density of 816.0 A/dm2. Apparently, the carbon steel wire surface properties (i.e. appearance, surface morphology and oxidation state) can be modified by controlling the current density, and the pickling under the current density of 816.0 A/dm2 can keep the steel wire shining with lamella surface morphology, thus providing functionality for subsequent coating.