This research compares the addition of some oxidant agents such as Fe2+, H2O2 and mixture from both to aqueous solution of dispersive yellow 42 dye, which regarded as an organic contaminant. This work performed during the dark reaction and photo reaction under artificial UV-A light (HPML -125 watt). In reality, the addition of the oxidant agents leaded to raise the light resistance of this dye to decolorize, this results can be used to increase the life time for textile materials which painted by this dye. The removal percentage without addition oxidant agent at 20 oC was decreased from 32.710 % to 21.445, 11.439 and 8.785% for addition Fe2+, H2O2 and mixing of both respectively. Moreover, the decolorization percentage for mention materials was depressed from 94.444 to 60.869, 4.163 and 16.044 respectively. The effect of temperature determined with chose Fe2+ as oxidant agent and compared with reaction without any addition, because the change is less compared with the other studied cases. The kinetic study of the photo-decolorization process of this dye demonstrated that the generated response is pseudo-first order. The Fenton and photo-Fenton improve the resistance of dye to decolorize during illuminated by light.The dye removal rates depress with the temperature increases from 288 K to 303 K; that due to the dark reaction is exothermic, nonspontaneous and obeys the physical adsorption depending on the values of enthalpy and free energy. In the contrast, the responsed of photodecolorization for this dye is found to be endothermic m non spontaneous and less random.