This letter proposes a new method of determining equivalent configuration. The method is called "the method of dividing the total spin groups". The rules are as follows: (1) Find L to determine the spectrum terms for a given total spin quantum number S(S =N/2, N/2 -1,…, 0 or 112), which are grouped from large to small, for S determines Nand Nfor each group. Next find ML~α and ML~β according to rule (2) to find Land L. Finally