Six optimized stable 3, 6-bis(1H-1, 2, 3, 4-tetrazol-5-yl-amino)-1, 2, 4, 5-tetrazine (BTATz) dimers were found on the potential energy surface and their electronic structures have been obtained by using density functional theory (DFT) at the B3LYP/6-31G^* level. The largest corrected intermolecular interaction energy of the dimer calculated with basis set superposition error correction (BSSE) and zero point energy (ZPE) correction is -68.82 kJ·mol^-1. The natural bond orbital (NBO) analysis was performed to reveal the origin of the interaction. Based on the vibrational analysis, the changes of thermodynamic properties from the monomer to dimer with the temperature ranging from 200.0 K to 800.0 K have been obtained using the statistical thermodynamic method, founding that the strong hydrogen bonds dominantly contribute to the dimers. The dimerization process can occur spontaneously over the temperature from 200 K to 400 K.