Abstract: The ligand field energy has been calculated in this paper. Taking two or three terms from the eigenvalue function expansion of intermediate field under condition of neglecting the interaction of different configurations, the result approaching that from total analysis has been obtained.The energy level correlatograph of ligand fielld has also been established and a method to delimit the areas of weak, intermediate and strong field has been proposed.It is found that many complexes of transition metals of the 4th period,especialy those of iron group elements, are intermediate compexes.