The characteristics of post-cathode plasma maintained by a self-made DC short glow-discharge plasma generator with grid electrodes were measured by optical emission spectroscopy. The discharge existed in an abnormal glow discharge mode at a voltage of 250–400 V and a helium pressure of 3–15 Torr and a discharge gap of 3 mm. The results indicate that the intensity distribution of helium atom spectral lines in the post-cathode space differs from that in the post-anode space. The temperature of electron excitation in the post-cathode plasma reaches its peak of 1500–3000K at 5–6 mm from the grid cathode. The difference in the intensity distributions of helium atom spectral lines in the post-cathode and post-anode spaces is associated with electron generation mechanism in these cases.