This paper investigated the production of biohydrogen from Imperata cylindrica, using stoichiometric equilibrium model. The stoichiometric equilibrium model uses biomass ultimate analysis, thermodynamic equilibrium and elemental balance on biomass gasification reaction. The sensitivity analysis was studied over a wide range of operating conditions involving temperature (250 – 1500 °C), pressure (1 – 5 atm) and Steam to fuel ratio (0-5). The result shows biohydrogen and other biogas product were sensitive to temperature and steam-feed ratio, whereas effect of pressure is negligible. The operating condition for optimal biohydrogen production in moles (23%) was atmospheric pressure, temperature, 1500 °C and steam-feed ratio, 5. Biogas product mixtures are H2, 23%, CO, 17%, CO2, 12% CH4, 0% and H2O, 60%. Increase in steam-feed ratio (0, 1, 2, 3, 4 and 5) significantly increase the biohydrogen by 1381%, 90%, 46%, 31% and 24%. The stoichiometry equilibrium model could effectively be used in determining biohydrogen production and its sensitivity to temperature and steam.