Copper was used as a non-inert cathode material in a Cathode/Fe3+ /peroxymonosulfate(PMS) system, and the performance of this novel Cu-cathode/Fe3+/PMS system was tested with a typical iodinated X-ray contrast media (iohexol) as target organics. The reaction mechanisms and the iohexol degradation pathways were investigated. The operational conditions of Cu-cathode/Fe3+ /PMS process on iohexol degradation were optimized to be 1.0 mM Fe3+ dosage, 3.0 mM PMS dosage and 0.50 mA/cm(2) of current input. The much lower current applied in the present study than previous reports would help to save energy and be more economical. Compared with typical inert cathode (Pt-cathode), the Cu-cathode/Fe3+/PMS process has better performance on both iohexol removal and deiodination, due to that Cu-cathode participated in Fe+ regeneration and PMS activation via surface Cu-o-Cu+ (s)-Cu2+-Cu-o redox cycle. Fe2+ could be produced via reactions between Fe3+ and Cu/ Cu+ (s) as well as cathodic reduction of Fe3+. SO4 center dot- was generated from PMS activation by Fe2+, Cu/Cu+ (s) and cathodic reduction. (OH)-O-center dot was also generated in this process but SO4 center dot- played a dominant role in iohexol degradation. The intermediate products of iohexol and its transformation pathways were complex due to the varied reaction mechanisms involving both oxidation and reduction in Cu-cathode/Fe3+ /PMS process.