The density functional theory（DFT） was used to study molecule and crystal of bis-(5-nitro-tetrazolato) tetraammine cobalt (Ⅲ) perchlorate (BNCP). DFT calculations of BNCP were performed using four different spin-restricted functionals (SVWN5,PBE,TPSS and B3LYP) with the 6-31G^**as the basis set. The results show that the TPSS (Tao,Perdew,Staroverov and Scuseria) functional best reproduce the experimental geometries. At the same time,the crystalline of BNCP was studied by PW91 of DMOL³. Then,the electronic structure of molecule and density of state,lattice energy,thermodynamic parameters of BNCP crystal were explored. The results show that the metal-ligand interaction in the title complex is covalent. And the frontier band consisted in the main of perchlorate ion,so it is the most active part of the compound. Meanwhile,the relationship between the temperature and thermodynamic parameters was obtained.