In this study, using the plasma generated from the pulsed discharge process, we examined the possibility of simultaneous degradations of dye substance and COD component in the landfill waste water. Furthermore, the possibility of sterilization by the plasma was investigated in the experiments. Experiments were performed to investigate the effects of voltage, repetition rate, charging time and O2 coexistence on the sterilization and degradations of COD and dye substance. The experimental results show that the sterilization and simultaneous degradations of the dye substance and COD are possible by the plasma and the dye substance is easily decomposed by the plasma from COD. The degradations of the dye substance and COD were enhanced by the presence of O2, while the effect on the dye substance degradation is larger than COD degradation. The results reveal that sterilization is possible by plasma, and E. coli is completely dead as compared with the bacteria is difficult to kill completely by the plasma.