Through ultrasoft plane-wave pseudopotential method of first-principle of density functional theory,crystal structure of BN is geometrically optimized and the obtained crystal lattice parameter is 0.3593nm.On the basis of optimized structure and by calculation,its energy gap is 4.654 eV and it belongs to indirect wideband energy gap semiconductor.Under zero temperature and zero pressure,its elastic constant is C11=804.6 GPa,C12=161.2 GPa,C44=463.9 GPa and its elastic modulus B0=375.7 GPa.According to approx...