In this study, the twin imidazolyl ionic liquid [C₂(Bim)₁₀]Br₂ was successfully prepared through the substitution reaction of 1, 10-dibromodecane with 1-propyl-2-methylimidazole imidazole. The molecular structure was confirmed to be intact, and the thermal stability was good by infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and thermogrirmetric analysis. The corrosion inhibition behavior of this ionic liquid on N80 steel in 1 mol/L HCl solution was systematically investigated via static mass loss measurement, electrochemical analysis and surface characterization after corrosion. The results show that when the concentration of the corrosion inhibitor is 50 mg/L, the corrosion inhibition efficiency reaches above 70%. The efficiency gradually increases with the increase of concentration. When it reaches 200 mg/L, it tends to stabilize after reaching 90%. [C₂(Bim)₁₀]Br₂ can act on the reactions both on anode and cathode simultaneously, comprehensively inhibiting the corrosion process and thus belongs to a mixed type of corrosion inhibitor. The corrosion morphology of the steel sheet with the addition of corrosion inhibitors was significantly improved, the contact angle increased, and the characteristic peak of Fe—N bonds appeared in the X-ray photoelectron spectroscopy, revealing the chemical coordination adsorption mechanism between the N atoms of the imidazole ring and Fe on the surface of the steel sheet. Molecular simulation shows that this corrosion inhibitor promotes electron transfer through a narrow energy gap (4.955 eV), preferentially adsorbs parallel to the iron surface (1.79 nm), and forms a stable protective film relying on Van der Waals forces, effectively blocking corrosive media and demonstrating excellent corrosion inhibition performance.