Hydrogen production from an ethanol solution by pulsed high voltage spark discharge was optimized by varying the material of plate electrode. It is the first time that metal work function has been used in hydrogen production by plasma reforming. With low work function metal plate electrode, both energy efficiency and hydrogen yield can be increased. The flow rate and the percentage concentration of hydrogen were achieved 1.3 L/min and 75% respectively while discharging with zinc plate electrode for hydrogen production, which is much better than traditional stainless steel electrodes at the same conditions. The analysis of emission spectra was also accomplished in this work. All the intensity of existing spectral lines showed a decline with higher work function metal as plate electrode, and H-center dot may be the key to the process of hydrogen production. Additionally, electron temperature and density were also estimated. Both of which were increased with lower work function metal plate electrodes. The electron temperature and density can reach 24,000 K, 7.5 x 10(18) cm(-3) respectively. (C) 2016 Elsevier Ltd. All rights reserved.