The needs energy for fossil fuels continues to increase in people's lives and industry. Fossil energy that cannot be renewed and has an impact on environmental damage needs to be sought alternatives from renewable energy, one of which is hydrogen because it is more environmentally friendly and does not cause air pollution. Hydrogen production through water electrolysis is a processof equicurity of water molecules into hydrogen and oxygen gases using electric current. In this study aims to determine the optimum condition of hydrogen gas produced, which is influenced by electrolyte concentration, time and number of electrode plates with the method used that is electrolysis. Hydrogen gas concentrations are used by MQ-8 gas sensors and dry cell generators as gas production reactors. In this study, Cu/Al electrode plate was used because it has good electrical conductivity as electrode and NaNO3 is used as electrolyte. The current and voltage used in this electrolysis process remained at 0.6 ampere and 2 volts for 1 hour. The results of the measurement of optimum conditions using the RSM program obtained the optimum concentration of hydrogen gas at the number of plates 3/3 (Cu/Al) namely at the concentration of NaNO3 1 M and time 60 minutes with a hydrogen gas concentration of 75.8907 ppm and the result verification of 76 ppm, while on the number of plates 4/4 (Cu/Al) obtained hydrogen gas concentration of 129,841 ppm and verification of 130 ppm at NaNO3 concentration 1 M and time 60 minutes. Based on the data shows the prediction of optimum solution suggested by RSM program is good enough.