Through general gradient approximate plane wave ultra-soft pseudopotential technology under the framework of density functional theory, geometric structure of unit space is optimized, BaWO of Tungstate mineral structure, energy band structure and electronic structure of its basic state are calculated, the research shows that BaWO has direct bandgap structure and its bandgap width is 4.5eV, that the valence band at Fermi surface is mainly composed of electrons on W5p and O2p state and that conduction band chiefly consists of W5d and O2p. According to crystalline field theory and molecular orbit theory, molecular orbit bonding of the crystal of Barium Tungstate is analyzed, the calculated results of which are better fitting for the state density pattern.