This study aims to remove reactive blue dye (R.B) from simulated wastewater by utilizing advanced oxidation processes (AOPs) using a photo-Fenton (UV/H2O2/Fe+2) system. A photo-reactor containing four fixed UV lamps had been employed in a batch and continuous mode under the effect of several operating variables (dosage of H2O2; dosage FeSO4; pH; temperature; irradiation time). Response surface methodology (Box–Behnken design) and Portable Statgraphics Centurion statistical software were used to design the experiments and conducting the mathematical correlation of the required responses as well as the interaction effects among variables. The optimal conditions of the operating variables; dosage hydrogen peroxide, ferrous sulphate, pH, temperature and irradiation time were 78 ppm, 20 ppm, 3, 40°C and 90 min, respectively which give 84.82% of removal efficiency. Then, the effect of light intensity and distance from a UV source were studied at optimum conditions in the batch photo-reactor where the highest dye removal efficacy was obtained at a light intensity of 24 w and a distance of 15cm. For continuous system, two operating conditions were studied, the direction of the light radiation and the flow rate which proofed that the dye removal efficiency decreased with an increase of flow rate and the top direction compared to the side direction of the light where the removal percentage of (R.B) was 100% for the flow rate of 10 ml/min while it was 84.16% for a flow rate of 50 ml/min. The results show that the photo-Fenton method is an effective treatment method of Wastewater containing dyes.