Abstract: The DFT-B3LPY method, with basis set 6-31G*, is employed to calculate the structures and properties for aromatic explosives containing -NO2groups, nitro derivatives of benzene and nitro derivatives of aminobenzene. It is found that there is a parallel relationship between experimental impact sensitivity and bond order of the weakest C-NO2 bond in a molecule in each series. Previously, based on semiempirical MO calculations,“the principle of the smallest bond order (PSBO)”has been proposed by us to identify the relative magnitudes of impact sensitivity of a series of explosive compoundswith similarmolecular structures. Here, PSBO is verified powerfully fromtheab initiocalculations for title compounds.