In this work, the degradation of an organic dye, Rhodamine B, was studied throughout Fenton reaction. The investigated process was optimized by a Response Surface Methodology (RSM), which study model and optimize the influence of several experimental parameters on the dye degradation process. The main factors (variables) were the concentration of Fe, the initial concentration of H2O2 and initial PH of the solution. So that, the experimental design was performed at 5 levels of the parameters and 18 experiments were designed. The optimum conditions were determined by RSM after the eliminating of the non-significant terms from the model. The optimum ranges of the main parameters were found to be 490-530 (µl) for [Fe2+], 550-600 (µl) for [H2O2], and 3-4 for PH, respectively.