The present study suggests that the thermal decomposition of 5-nitro-1-hydrogen-tetrazole might be the main contribution to the N-2 releasing process of 5-nitro-tetrazole's decomposition. Three reaction channels of 5-nitro-1-hydrogen-tetrazole were revealed in ab initio molecular dynamics (MD) simulations. The direct ring rupture of N1-N2 bond breaking has the lowest energy barrier at the first reaction step and is expected to dominate the thermal decomposition. Hydrogen-transfer leading process has a relatively higher energy barrier for the first step. However, the proton-transfer rate could increase dramatically due to the quantum tunneling effect. The direct ring-opening reaction through the C5-N4 bond breaking is less important for its very high activation energy. (C) 2002 Published by Elsevier Science B.V.