Abstract: The electronic structural properties of 1，1-diamino dinitroethylene crystal have been studied by the DFT method with B3LYP function. The calculated crystal energy is -05.81 kJ/mol，which is comparable to the reference value. The frontier bands are quite flat，indicating that the molecular states are hardly perturbed by the crystalline environment. The distribution of electronic charges determines that the molecules pack through head-end to form wave-shaped layers with extensive intermolecular hydrogen bonding within the layers and ordinary van der Waals interactions between the layers. Judged by the value of band gap of 4.0 eV，it could be predicted that the conductivity of DADNE is between the semiconductor and insulator. The frontier orbital consists of atomic orbitals of C-NO2 group，indicating that there exists a stronger conjugation among the molecules and that C-NO2 is the region with high reactivity. The population of C-NO2 bond is much less than those of all the other bonds and therefore the detonation is initiated by the breakdown of this bond.