Abstarct: Atmospheric pressure cold plasma is more popular than other technologies due to its lack of secondary pollution, optimal energy efficiency, no need for a vacuum system, and its low cost. The advanced oxidation process in plasma technology is baxsed on the production of reactive species, especially hydroxyl radicals, ultraviolet radiation and shock waves. Hydroxyl radicals are very strong oxidizers, so electrical discharge is used inside or at the water-gas interface. One way to produce cold plasma is to use spark electrical discharge and it commonly used for textiles wastewater treatment. In this research, we designed two types of reactors to produce spark plasma and investigated the effect of physical and chemical parameters such as electrode material, their distance from each other, the effect of pH, time and pollutant concentration on the rate of degradation and decolorization of methyl orange solution. The type of discharge from the voltage-current curve has been analyzed and the plasma power is calculated. The species produced at different times using optical emission spectroscopy have been identified and studied.