Using the first-principle method within the generalized gradient approximation, in this paper we study the band structure, state density and doping level of transparent conductive oxide CuScO2. The calculated results show that the valence band of CuScO2 is composed mainly of 3d of Cu, and 2p of O; while the conduct band is comprised mainly of 3d of Sc. Through the +U correction, with the increase of the value of U, the conduct band of CuScO2 becomes split, and results in the enlarged band gap, which shows that the +U correction can improve the band gap of CuScO2. By comparing all kinds of dopant level in CuScO2, it found that the substitution of Mg for Sc can effectively improve the p-type conductivity in CuScO2.