Abstract: A general method to calculate the triple differential cross sections(TDCS) for electron impact ionization of hydrogen atom,hydrogenicion He⁺, helium atom and helium-like ion Li⁺is given by generalizing the theoretical framework developed by Brauner et al. The present TDCS results of H, He⁺, He and Li⁺are compared with those of other theoretical models and/or experiment, and good agreements have been found.

Key words: (e,2e), electron impact ionization, triple differential cross sections