In our previous studies of a plasma reformer system, the effects of temperature of the reactants and input voltage have not been considered. In the present investigation, the plasma reformer system has been modified to study the influence of the reactants' temperature and input voltage on hydrogen production experimentally. The plasma reformer system includes a supersonic atomizer, a plasma generator, and a controlling device. In the experiment, the operating parameters include the temperature of the reactants and the input voltage. The temperature of the reactants varies from 25 °C to 50 °C, and the input voltage ranges from 12.5 V to 14.5 V. Results show that the increase in temperature of the reactants and input voltage will improve the production of hydrogen. In addition, the improvement of heating on the reactants shows significant influence on hydrogen production.