This study carried out a laboratory scale plasma reactor about the characteristics of chemically oxidative species (․OH, H2O2 and O3) produced in dielectric barrier discharge plasma. It was studied the influence of various parameters such as gas type, 1st voltage, oxygen flow rate, electric conductivity and pH of solution for the generation of the oxidant. H2O2 and O3.) H2O2 and O3 was measured by direct assay using absorption spectrophotometry. OH radical was measured indirectly by measuring the degradation of the RNO (N-Dimethyl-4-nitrosoaniline, indicator of the generation of OH radical). The experimental results showed that the effect of influent gases on RNO degradation was ranked in the following order: oxygen > air >> argon. The optimum 1st voltage for RNO degradation were 90 V. As the increased of 1st voltage, generated H2O2 and O3 concentration were increased. The intensity of the UV light emitted from oxygen-plasma discharge was lower than that of the sun light. The generated hydrogen peroxide concentration and ozone concentration was not high. Therefore it is suggested that the main mechanism of oxidation of the oxygen-plasma process is OH radical. The conductivity of the solution did not affected the generation of oxidative species. The higher pH, the lower H2O2 and O3 generation were observed. However, RNO degradation was not varied with the change of the solution pH.