Hydrogen production from methane reforming using the partial oxidation reaction is carried out using a bipolar pulse-driven plasma reactor operating at atmospheric pressure. The influence of axial and radial injections of CH(4) and O(2) on the reforming performance is investigated in conjunction with the spatial distribution of their spectral emissions by varying the O(2)/C ratio at a fixed discharge power. With increasing the O(2)/C ratio, the axial injection achieves the better conversion and efficiency. The measurement of spectral emissions reveals that the higher efficiency of axial injection is caused by its efficient use of oxidation reaction heat.