<p>The aim of this study was to evaluate the corrosion inhibition performance of alkyl pyridine bromide ionic liquids ([C_<i>n</i>Py]Br <i>n</i> = 4, 8, 12) on mild steel in 3.5 wt.% NaCl solution. The results showed that [C_<i>n</i>Py]Br had a significant corrosion inhibition effect on carbon steel, and its corrosion inhibition effect was enhanced with the increase of alkyl chain length and concentration, and the optimum corrosion inhibition efficiency of [C₁₂Py]Br was 85.5%. Electrochemical measurements showed that it is a hybrid corrosion inhibitor, which conforms to the Langmuir adsorption model and exhibits chemisorption and physisorption on the metal surface. Surface analyses, including scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS), and quantum chemical calculations confirmed that [C_<i>n</i>Py]Br was able to generate a protective layer on the surface of mild steel, effectively preventing corrosion. In addition, the adsorption behavior of inhibitor molecules on the Fe(110) surface was also analyzed using molecular dynamics (MD) simulation, which was in good agreement with the corrosion inhibition efficiency determined by the experimental method.</p>