To strip off iron-oxide scab from strip-steed surface by means of electrolysis in neutral sodium sulfate solution (neutral electrolytic descaling) has been investigated in Shanghai No.4 Cold-Strip Steel Works in cooperation with Shanghai Chiaotung University.A general view about ite mechanism is given in this report.The electrolytic deeoa,ling in neutral solution is mainly due to electrochemical action, and cannot be considered as fundamentally acid pickling.In the process of electrolytic descaling, strip-steel acts as a cathode first, and then as an anode.The ferric iron in its surface oxide layer is reduced eleotrolytically to ferroas or metallic iron and may also be reduced by nascent hydrogen evolved at the electrode during the cathodio treatment, after which the surface of strip-steel becomes loose and can be easily stripped off.While the strip-steel acts as an anode, it undergoes anodic oxidation to form Fe²⁺ and then Fe³⁺，and precipitateKl as ferric hydroxide.The evolution of hydrogen bubbles may also have some beneficial effect on destroying iron oxide scale.