The objcetive of this study is to propose an optimum operating conditions in the treatment of plate wastewater by Fenton''s oxidation and membrane separation process. Optimum operating conditions for Fenton''s oxidation were pH 4, a reaction time of 30 min and the dosage of H₂O₂ and FeSO₄·7H₂O was 550 mg/L and 500mg/L, respectively. Membrane separation was conducted as post-treatment using supernatant after pre-treatment by Fenton''s oxidation. COD could be reduced from 70.89 mg/L(RO feed) to 14.44 mg/L(79.63% removal). CN^- and Zn²⁺ were removed from 1.45 mg/L and 48.00 mg/L in the RO feed to 0.16 mg/L and 1.60 mg/L in the treated water, respectively. Excellent CN^- (88.97%) and Zn²⁺(96.67%) removals by RO were obtained.