We present a detailed theoretical study for the structural and electronic properties of the new synthesized hard material Ta 2 N 3 under pressure ranging from 0GPa to 100GPa using the plane-wave pseudopotential density functional theory by CASTEP code in this paper. The results at zero pressure are in good agreement with the available theoretical and experimental values. We find that the Ta 2 N 3 will undergo phase transition from tetragonal to orthorhombic phase at a pressure of 10.6GPa. There are strong covalent bonds between N and Ta atoms in Ta 2 N 3 , and the high pressure will reduce the hybridization energy.