Abstract: Multi-attribute group decision-making problems are considered where information on both attribute weights and value scores of consequences is incomplete. In group decision analysis, if preference information about alternatives is provided by participants, it should be verified whether there exist compromise weights that can support all the preference relations. The different compromise weight vectors may differ for the ranking of the alternatives. In the case that compromise weights exist, the method is proposed to find out all the compromise weight vectors in order to rank the alternatives. Based on the new feasible domain of attribute weights determined by all the compromise weight vectors and the incomplete information on value scores of consequences, dominance relations between alternatives are checked by a nonlinear goal programming model which can be transformed into a linear one by adopting a transformation. The checked dominance relations uniformly hold for all compromise weight vectors and the incomplete information on value scores of consequences. A final ranking of the alternatives can be obtained by aggregating these dominance relations.