A new combination method is introduced for solving the combination problem of experts' conflict opinions of military communication network effectiveness evaluation in this paper. For the new method, firstly, the quantification of evaluation opinions of experts is made based on multi-attribute group decision-making level evaluation model, then the basic probability distribute functions of each index are calculated based on the experts' evaluation opinions. Secondly, the basic probability distribute functions are combined based on the improved D-S model. Finally, a case is analyzed. The results show that the problem such as rejecting by one condition is solved and the new method is more reliable compared to the classic combination rule of D-S model. The opinions of experts can be reflected objectively and impersonally when the new method is used in combining the experts' opinions in the evaluation of military communication networks effectiveness.