In this study, the possibility and the optimal conditions for treating slurry type piggery wastewater using supercritical water oxidation were tested in the laboratory. The results could be summarized as follows; The slurry type piggery wastewater, which was diluted 50 times, was treated most effectively at the pressure of 300 bar, the temperature of $550^{circ}C$ and the residence time of 10 minutes. The air saturated water was injected, as an oxidizing agent, and the removal efficiencies of $COD_{Cr}$, T-N, $NH_4^+$-N and T-Pattheoptimal conditions were 92, 40, 59 and 100%, respectively. Therefore, analte rnativemea suremu stbetaken to improve theremo valefficiency of the nitrogen compounds.