The study encompasses the synthesis of an ionic liquid corrosion inhibitor using the ion exchange method. Its impact on the corrosion and hydrogen permeation behaviour of X80 pipeline steel in a CO 2 environment is thoroughly investigated. The findings reveal that the corrosion resistance and hydrogen atom diffusion of X80 pipeline steel exhibit an initial decline, followed by an increase with escalating inhibitor concentration. The nadir values are recorded at an inhibitor concentration of 500 mg·L −1 , attaining a remarkable maximum inhibition efficiency of 97%. Following the addition of corrosion inhibitors, the formation of corrosion products notably decreases, indicating a positive inhibition effect on both corrosion and hydrogen permeation. Additionally, a correlation is successfully established between hydrogen permeation parameters and inhibitor concentration.