For a maximal subgroup m of a finite group g the normal index of m is the order of a chief factor h / k where h is minimal in the set of supplements of m in g . in this paper we can obtain some results about solvability and supersolvability by using the normal indexes of maximal subgroups of finite groups 有限群g的极大子群m的正规指数是指g的主因子h k的阶，其中h为m在g中的极小正规补。本文利用正规指数的概念，获得有限群可解，超可解的若干结果。
