At present work, aqueous solutions of azo dye Reactive yellow 86 (RY86) were treated with Fenton reagent. The efficiency of treatment was evaluated by color alteration and mineralization of the dye. A detailed investigation of photodegradation of Reactive Yellow 86 using H2O2/Fe2+ has been carried out. The reduction of color was determined by UV-VIS spectrophotometer and the results showed that the dye rapidly lost the color while the doses were increased. Results indicate that dye degradation is dependent on concentration of Dye (RY86), photocatalyst (Fenton reagent), H2O2 and pH of the experimental solutions. The optimum conditions for the photobleaching of dye had been established. The kinetics of degradation of the dye in the dilute aqueous solutions follows first order kinetics. The results indicated that the treatment of the dye by Photo-Fenton reagent was efficient at optimum conditions.