This paper briefly describes the theoretical deduction of the cross section of electron-ion impact excitation in Coulomb-Born approximation. The LS coupling representation of electron-ion system is used, the exchange effect is taken into account and the angular factors of collision matrix elements are treated in detail. The corresponding code-CBX(9) is programed. The situations of complex ions and incident electrons with lower energy can be computed by the code, which has wide applicability. The computational results are in well agreement with ones obtained from the other methods.