Abstract: Under experimental conditions, Mn²⁺/Fe²⁺/Cu²⁺/Zn²⁺/Al³⁺/Y³⁺/La³⁺(especially for Y³⁺and La³⁺),KMnO₄/K₂S₂O₈/KClO₃/KClO₄/KBrO₃/KIO₃ can accelerate the photochemical degradation of 4chlorophenol(4CP), and this acceleration effect increases with the increase of concentration of metal ions and oxidants. KIO₄ can inhibit the photochemical degradation of 4CP, and this inhibition effect increases with the increase of the concentration of KIO₄. Cooperative effect of KClO₃/KBrO³⁺Y³⁺ on the photochemical degradation of 4CP is more striking. Without illumination, KMnO₄, KIO₄+Mn²⁺/Fe²⁺ can cause 4CP to be oxygenated at once, the effects of KMnO₄ and KIO₄+Mn²⁺ are especially striking.

Key words: metal ions, photochemical degradation, 4chlorophenol, oxidants