Base on it, we present two kinds of concepts of non-commonity, and give the evaluation method by optimization theories and normalization, which overcomes the adverse effect of different non-commonity.

Considering the consistency and similarity of judgment matrix,the definition of consensus degree in AHP group decision-making,which is used as the basis to determine whether to stop the interactive process,is proposed.

In order to make the decision-making more objective and accurate,basing on the distinction between experts static weights and experts dynamic weights,the paper researches the method to decide experts dynamic weights in interactive decision-making and brings out a definition of consensus degree.

This article starts from constructing consensus degree model and group s difference coefficient(GDC),then analyzes the effect of GDC on the mediation mechanism for consensus process,and finally proposes that identifying group divergence in evaluat- ing a given alternative is the key element of this research.