Abstract: A study of electron impact excitation of charged ions is reported here.Electron collision strengths and oscillator strengths have been calculated using plane—wave and Coulomb—wave Born approximation with configuration interactions. The corresponding programs MCPBA(9) and MCCBX(9) have been compiled. As an example, we give the calculation results of Nc-like Ge ion with 27 levels and 4 configurations from its ground state. 13 different processes which contain direct collision only have been calculated with MCPBA (9). The collision strengths of 26 different processes which include exchange collisions have also been calculated with MCPBA (9). The effect of wavefunction on the collision strengths has been examined. Our results are compared with the available results of distorted wave. It has been found from the result that the accuracy of the target wave function is much more important than that of the collision electron wave function.