The current study aimed to evaluate the performance of sodium persulfate to treat stabilized landfill leachate. Factorial design with response surface methodology (RSM) was used to evaluate the interaction between operational conditions, such as persulfate dosage, pH, and reaction time, to obtain the optimum conditions. The two quadratic models obtained by RSM for COD and NH₃–N removal proved to be significant models (P<0.0001). The optimum conditions obtained included a reaction time of 60 min, 4.97g S₂O₈²⁻, dosage and pH 7. The experimental results were corresponding well with predicted models (COD and NH₃–N removal rates of 45%, and 47%, respectively. The results revealed that persulfate oxidation is an efficient for pretreatment of stabilized landfill leachate.