High CODcr concentration and brown color of the clarified effluent of piggery wastewater cause the problems for recycle or discharge of treated wastewater. Heterogeneous photocatalytic treatment was applied for complete oxidation and decolorization of the effluent which contains a large amount of non-biodegradable organics (NBOs). The CODcr, BOD, TOC and color were analyzed with processes to evaluate its performance and investigate its optimum condition for higher efficiency. The UV/TiO₂/H₂O₂slung reactor was operated in batch manner. The highest removal efficiency was obtained at the condition of pH 2, TiO₂ 1.0 wt% and H₂O₂ 300 ㎖/L. However the least-cost operation was observed at the condition of pH 4, TiO₂ 0.6 wt% and H₂O₂300 ㎖/L. The photocatalytic oxidation rate of NBOs in the biologically-treated piggery slurry followed the pseudo-first order kinetic curve. It showed the removal efficiency of color was much higher than that of CODcr and TOC of NBOs. Color removal efficiency has reached 99% after three hours since the reaction began. The CODcr and TOC concentration decreased with the exponential increase of the irradiation time and the BOD_5/CODcr ratio. The photocatalytic system can be referred to as one of potential systems to treated piggery wastewater for reuse. However further study for practical application to field should be pursued in near future.