<p>The influence of pH on the fretting corrosion behavior of the 5083-H112 high-strength aluminum alloy has been systematically investigated. A coupled system integrating an in situ electrochemical workstation with a fretting wear test rig was employed, and tribological theory combined with electrochemical analysis was used to explore the underlying mechanisms under varying pH conditions. The results indicated that the coefficient of friction was lowest at pH&#xa0;7 and higher in both acidic and alkaline environments. Fretting damage and corrosion rates were elevated in acidic and alkaline media compared to neutral conditions, reflecting the role of surface films: soluble AlCl₃ dominated in acidic solutions, Al₂O₃ and Al(OH)₃ coexisted to provide strong protection in near-neutral solutions, and OH^- promoted a stable but less protective Al(OH)₃ layer in alkaline solutions. Dominant wear mechanisms included abrasive wear with fatigue cracking in acidic media, abrasive wear alone in neutral media, and abrasive wear combined with plastic deformation in alkaline media.</p>