The inner-sphere reorganization energies (REs) of diatondc molecules in gaseous phase electron transfer (ET)process have been calculated in terms of Morse function scale model presented in this paper, the struCtural reorganization index (activated radius of the reduCed molecule) is given, the parameters involved can be determined via ah initio calculations at HFSCF levels (6-31G, 6-31G^*, DZ and DZP (d)), The inner-sphere RE values are calibrated by comparing molecular structural parameters (bond dissociation energies, force constants) with experimental data. Results indicate that ah initio calculation values are better agreement with experimental ones, and are found to be accurate to within + l.5kcal/mol or better. This method not only improves classical model but also gets around the difficulties in obtaining available experimental data and constitutes an accurate ah initio method in calculating inner-sphere REs of diatondc molecules in gaseous ET process.