Using the first-principles plane-wave pseudopotential method based on the density functional theory, the electronic structure and the point defects structure of V into Ni3Al alloy were studied. The approximate algorithm of Ni3Al alloy was selected by comparing experimental results with the calculation. The lattice constant, the formation enthalpies, cohesive energies, formation energies and equilibrium concentration of point defects, density of states of the supercell and charge density were calculated. The calculation results show that anti-site defects are more easily formed than vacancy defects, NiAl is the most important anti-site defect, and the Al-sites are the defects more easily formed than Ni-sites in the Ni3Al alloy. The equilibrium concentration of vacancy defects in Ni3Al alloy at 1400 K is far below that of the anti-site defects. V atoms into Ni3Al alloy system can increase the stability of the alloy.