In this study, gamma ray irradiation was used to treat livestock wastewater treatment. At 50kGy, maximum dose of gamma ray, TS and TSS were reduced 2% and 38%. SCOD and TCOD also were reduced 10% and 9%. T-N, NH3-N and NO3-N were decreased, but NO2-N was increased about 74%. It is considered that NH3-N and NO3-N were convert to NO2-N, because NO2-N will be able to convert to N2 gas easily. From these results. We can expect that gamma ray irradiation is useful in applying biological treatment process of livestock wastewater.