Abstract: The numerical value of the electromagnetic interaction constant is calculated phenomenologically by means of Dirac large number D and Planck large number A,and the result tallies with the customary Value very well.In the dynamic model of the subquark structure of a lepton,because of the equi-valume surface deformation of a lepton caused by the movement of the subquarks in it,the symmetry breaking of electromgnetic interaction occurs,so that the"anomalous mass"and the "anomalous electric charge"of a lepton emerge and the value of α is no longer a constant but is changeable.The value of ΔQe反 can be calculated from Δme反> and that of the anomalous magnetic moment can also be done from both Δme反> and ΔQe反,which are near the experimental Values.And finally,the quantization conditions about Planck scale is discussed.