<p>This study systematically investigates the influence of chloride ion (Cl⁻) concentration on the galvanic corrosion of stainless steel using the wire beam electrode (WBE) technique. By fabricating stainless steel as a WBE to simulate its actual microscopic surface state during service, this study employs an electrochemical workstation to monitor key parameters—including potential distribution, current density, and galvanic current—on the electrode surface in real time across solutions with varying Cl⁻ concentrations (covering low, medium, and high Cl⁻ concentrations). The results demonstrate that, compared to the single stainless steel WBE, the coupled stainless steel WBE exhibits a significant increase in surface potential difference, a sharp rise in galvanic current density, and a marked expansion of active corrosion zones as the Cl⁻ concentration increases. This indicates that higher Cl⁻ concentrations substantially intensify the galvanic corrosion of stainless steel. The underlying mechanism is that elevated Cl⁻ levels more effectively disrupt the passive film on the stainless steel surface, thereby accelerating the anodic dissolution process. The WBE technique enables precise detection of micro-scale electrochemical changes on the material surface during galvanic corrosion processes. This approach provides robust experimental evidence for elucidating the mechanism by which Cl⁻ concentration affects stainless steel galvanic corrosion behavior. Furthermore, the acquired data establishes a critical theoretical foundation for formulating effective corrosion protection strategies and guiding material selection for stainless steel applications in chloride-containing environments.</p>