Journal impact factor is one of indicators of evaluation of academic journals.There is much different among impact factors of journals of different disciplines. Proportions of papers of each discipline among Multidisciplinary academic journals are different. It is more difficult for evaluation of Multidisciplinary academic journals. For more just and impartial, on basis of test of various sets of indicators, the set of impact factor exclusive of cited by itself, titles that cited the journal, and the halflife of cited time weighted separately by coefficient of 0.85,0.1 and 0.05 is more reasonable.