In this work, light emissions and radicals formed by plasma of contact glow discharge electrolysis were investigated. The plasma was generated by glow discharges at the tip of a Pt anode in contact with a sulfuric acid solution. Emissions of H atoms and OH radicals were observed when the applied voltage was above 430 V. When the applied voltage increased to 450 V, emissions of O atoms were additionally detected. The emission intensities of these radicals and atoms increased with the increasing applied voltage. When the applied voltage exceeded 460 V, thermal radiation from the Pt anode was apparent in the visible and near infrared region. Electron temperature of the plasma increased with the applied voltage from 1.0 x 10(4) to 1.5 x 10(4) K by comparison of the intensities of H-alpha and H-beta lines. The mean electron density was estimated to be 7.4 x 10(17) cm(-3) by the method of Stark broadening.