Abstract: Applying the definition of extra polarization and Mori's Brown motion equation,we got the secular motion equation for extra polarization from the nonequi-librium standpoint.We have solved the secular Eq.with the help of the assumption of equal effective ionic electric field.It shows not only the ion's radius but also the solution structure and solvent properties are responsible for the per-mittivity decrement.Using the present result,calculations are carried out for the systems of LiCl-CH₃OH,NaCl-CH₃OH,NaI-CH₃OH,NaCl-H₂O,LiCl-H₂O ,KCl-H₂O,NaI-HCONH₂,Comparison among the continuum theory,molecular theory and ours is made,it shows our result is better to the salted system of alchol and water