Effect of electrolytes on the decolorization of indigo carmine and on the production of H₂O₂ by pulsed discharge in air spraying water droplets was performed in sodium chloride and magnesium sulfate solutions. Peak voltage of the discharge decreased with increasing solution conductivity, but peak current and discharge energy increased. Decolorization rate and decolorization efficiency of indigo carmine and the yield of H₂O₂ decreased with increasing chloride and sulfate ion concentrations. It was found that the decolorization of indigo carmine and the production of H₂O₂ are affected by the ion concentration even in the case of discharge in air spraying water droplets. However it was less effective than that of discharge in water. Chloride ion was more effective than sulfate ion regarding the decrease of decolorization rate and the production of H₂O₂. Decolorization rate of indigo carmine was strongly related to the production of H₂O₂. These results also indicated that decolorization of indigo carmine depends on the production of hydroxyl radical.