The characteristics and the effects of oxygen on the decomposition of sodium acetate have been investigated by pulsed discharge in water droplet spray in O2 and N2 used as carrier gases in the reactor. Two experimental conditions of gas mixing ratios of O2/N2 = 10/90 and O2/N2 = 50/50 were performed to evaluate the effect of oxygen. In both conditions, acetate was decomposed by pulsed discharge in water droplet spray, and formate and the other products were detected as intermediate products. Formate was gradually decomposed with increased treatment time. Acetate decomposition rates after 10 h treatment in the gas mixing ratios of O2/N2 = 10/90 and O2/N2 = 50/50 were 39% and 80%, respectively, and TOC decomposition rates were 48% and 78%, respectively. It was found that it is possible to decompose sodium acetate. These results indicate that organic compounds which have a carbon-carbon single bond can be completely decomposed by this technology. Decomposition efficiencies in the gas mixing ratios of O2/N2 = 10/90 and O2/N2 = 50/50 were 43 μg/kJ and 97 μg/kJ, respectively. Decomposition efficiency in the gas mixing ratio of O2/N2 = 50/50 is about 2.2 times higher than that of the gas mixing ratio of O2/N2 = 10/90 . These obtained results show that oxygen plays important roles in enhancing the decomposition of organic compounds.