Abstract: A mathematical model was established to simulate the combustion of the premixed hydrogen and oxygen in this paper,and the influences of the ignition position,the reaction mechanism and elementary reaction kinetic parameters on the combustion process were analyzed. The results show that buoyancy has significant influence on the flame propagation. The top ignition method is more beneficial for controllable and safe eliminating of hydrogen. The amounts of consumed hydrogen are nearly equal when the flame propagates the same distance for the two ignition positions. Additionally, the predicted hydrogen combustion processes according to Marinov and Warnatz mechanisms show good consistency with each other. The HO₂ formation/consumption reactions are the limiting reactions in the Marinov and Warnatz mechanisms, and their reaction rates greatly affect the total reaction rate.