In order to treat the dyeing wastewater, the UV/TiO₂/H₂O₂ system was investigated, and proper protreatment methods were examined to reduce the load on the system considering economical and techical efficiency. Also, to obtain the maximize the removal efficiency of dyeing wastewater, optimal operating conditions for the photocatalytic degradation were investigated by using the responsed surface methodology(RSM) . The independent variables were TiO₂ dosage, H₂O₂ concentration and removal efficiency of dyeing wastewater was dependent variable. With the 2²-factional factorial experimental design, 11 experiments were carried out at various condition, with 4 factorial points, 3 center points and 4 axial points. Maximum removal efficiency(85%) of dyeing wastewater was obtained at TiO₂ dosage(1.82g/L), H₂O₂ concentration (980㎎/L) for photocatalytic oxidation reaction(20min).