Abstract: The greenhouse effect as well as its induced global warming is one of important global environmental issues. To control greenhouse gas CO₂, the decomposition of CO₂ by high frequency dielectric barrier discharge was studied. The effect of applied voltage, frequency, cooling method and CO₂ concentration on the decomposition characteristic of CO₂ was investigated. The results showed that the decomposition of CO₂ could be enhanced by increasing applied voltage or frequency within limits. Circulated water cooling or air cooling to reactor was helpful to decomposition of CO₂ for controlling the secondary reaction. Although decreasing the CO₂ concentration by mixing it with inert gases could increase the decomposition of CO₂, the energy efficiency reduced.