Abstract: The energy band structures and density of states of intrinsic CrSi2 and V-doped CrSi2 have been calculated using the first-principles pseudo-potential method based on density functional theory(DFT) with generalized gradient approximation(GGA).The calculated results show that CrSi2 is an indirect transition semiconductor with its narrow energy gap of 0.35eV;the density of state near the Fermi surface is mainly composed of Cr 3d and Si 3p state electron.After doping V,the Fermi level enters valence band,the width narrows with the indirect band gap width ΔEg=0.25eV.The density of state near the Fermi surface is mainly composed of Cr 3d,Si 3p and V 3d state electron.Atom Vbecomes the acceptor to contribute some holes at the top of valence band and CrSi2 change into p-type semiconductor and improves the electrical conductivity of material.