Objective To investigate the performance of pomelo peel extract in corrosion inhibition in 1 mol / L HCl. Methods A natural green corrosion inhibitor was extracted from pomelo peel using soxhlet extraction method, and the mechanism of corrosion inhibition of the extract was analyzed in a complex with 0. 01 mol / L KI. Weight-loss and Electrochemical tests were used. Results The result of weight-loss test showed that the corrosion inhibition of the extract to C38 steel was up to 93% , and it reached up to over 98% when used in a complex with 0. 01 mol / L KI. It was also shown that the adsorption of the inhibitor molecules on the surface of C38 steel obeyed Langrnuir isotherm. The Tafel polarization curves indicated that both anodic and cathodic corrosion processes were suppressed by the inhibitor. The EIS indicated that the charge transfer resistance increased with the increase of the inhibitor concentration. Conclusion Pomelo peel extract is a good corrosion inhibitor and the effect enhanced by the addition of halogen ions.