Plasma electrolytic borocarbonitriding (PEB/C/N) was successfully used to achieve ternary borocarbonitriding layer on industrial pure iron at the bath voltages of 340, 360V and 380V respectively. The morphology, composition, phase constituents and microhardness profiles of PEB/C/N layers were investigated. The influence of bath voltages on wear behaviors of PEB/C/N layers was evaluated by ball-disc friction and wear tester under dry sliding against ZrO₂ ball, and their wear mechanism were analyzed. The results show that the thickness and maximum hardness of PEB/C/N layer on pure iron increase with the increase of bath voltage. After 1h discharge treatment at 380V, the boride layer and transition layer of the PEB/C/N sample reach 26μm and 34μm respectively, and the maximum microhardness of PEB/C/N layer can reach 2318HV. The wear rate of PEB/C/N layer is only 1/10 of that of the pure iron substrate. The friction coefficient and wear rate of pure iron are greatly reduced after the PEB/C/N surface treatment, but the friction coefficient and wear rate of PEB/C/N layer vary little under different bath voltages.