Natural gas resources with high concentrations of carbon dioxide have been found in several areas, including Thailand. The reforming of carbon dioxide with methane should be a promising way to directly utilize the natural gas without any prior separation process, resulting in it being more economical in terms of cutting down the high cost of an additional separation unit and reducing the net emission of carbon dioxide as a greenhouse gas. The objective of the present work was to investigate the reforming of simulated natural gas via the nonthermal plasma process with the focus on hydrogen production. The reforming of simulated natural gas was conducted in an alternating current (AC) gliding arc reactor under ambient conditions. The feed composition of the simulated natural gas contained a CH₄/C₂H₆/C₃H₈/CO₂ molar ratio of 70/5/5/20. To investigate the effects of all gaseous hydrocarbons and CO₂ in the natural gas, the plasma reactor was operated with different feed compositions: pure CH₄, CH₄/He, CH₄/C₂H₆/He, CH₄/C₂H₆/C₃H₈/He, and CH₄/C₂H₆/C₃H₈/CO₂. In comparisons among all the studied systems, hydrogen selectivity was found to depend on the feed composition in the following order: CH₄/C₂H₆/C₃H₈/CO₂ > CH₄/C₂H₆/C₃H₈/He > pure CH₄ > CH₄/C₂H₆/He > CH₄/He. The maximum hydrogen concentration, about 6 mol%, was found in the CH₄/C₂H₆/C₃H₈/CO₂ system. In terms of energy consumption for converting all reactant molecules, the CH₄/C₂H₆/C₃H₈/CO₂ system required the lowest input energy in the range of 15 to 25 eV/molecule of reactants converted. For the simulated natural gas, the conversions of CH₄, C₂H₆, C₃H₈ and CO₂ increased with increasing applied voltage, but the CO and C₄H₁₀ selectivities decreased. An increase in frequency resulted in lowering the conversions of all reactants and the selectivities of H₂ and C₂H₂, whereas the selectivities of C₂H₄, C₄H₁₀ and CO tended to increase.