In this paper,it is suggested to use the mean effective attraction force exerted on the valence electrons by the atoms as a basis for the calculation of electronegativity.Taking the orbital function of hydrogen-like atom as the wroth-order approximate wave function of many-electron atoms,the present author derived a Formula for calculating electronegativities of atoms,which can also be applied to atoms in various valence states.With a few exceptions,all results obtained are close to those published in literature.