Abstract: To understand the pathways of Fe²⁺ regeneration during the Fenton oxidation of p-chlorophenol(4-CP), the change of the concentration of Fe²⁺ and the reduction of Fe³⁺ by the intermediates were studied.Fe²⁺ remained almost unchanged during the oxidation of 4-CP by the Fenton process.But in the presence of 1-propanol,the scavenger of •OH, Fe²⁺ sharply decreased to 10% at the end of the first minute. Analysis of the rate constants of Fe²⁺ and Fe³⁺ with H₂O₂, •OH, HO₂• and O^-₂• suggested that the net contribution of these radicals to Fe²⁺ regeneration was small and the reduction of Fe³⁺ by the intermediates of 4-CP oxidation was the main pathway of Fe²⁺ regeneration. Hydroquinone and benzoquinone were identified as the intermediates by HPLC. Hydroquinone could reduce Fe³⁺ quickly but benzoquinone could hardly reduce Fe³⁺.Hydroquinone was oxidized to form benzoquinone by Fe³⁺ and the ratio of hydroquinone to Fe³⁺ was 1∶2.This study is helpful to better understand the regeneration of Fe²⁺ in the Fenton process.