CO2 reforming of CH4 to synthesis gas was investigated by cold plasma jet (CPJ) only and combination of cold plasma jet with Ni/gamma-Al2O3 catalyst at atmospheric pressure. The higher selectivity of H-2 and CO, and higher energy efficiency was obtained by this novel process. The optimum experimental conditions are: CH4 = 3.33 Nl/min, CO2 = 5.00 Nl/min, N-2 = 8.33 Nl/min, and the input power at 770 W. The results showed that, for the plasma only, the conversions of CH4 and CO2 were 46% and 34%, the selectivities of CO and H-2 were 85% and 78%, the energy efficiency was 2.9 mmol/kJ, respectively; for the combination of cold plasma jet with Ni/gamma-Al2O3 catalyst, the conversions of CH4 and CO2 were increased by 14% and 6%, the yield of H-2 and CO increased by 18% and 11%, the energy efficiency reached at 3.7 mmol/kJ, respectively. And the catalyst hasn't accessorial heating. The CPJ method has the advantage of simple processing and is easy to be industrialized. (c) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.