The distributed cooperative situation analysis plays a significant role in the Campaign Planning of Joint Operations. Since the current environments of battlefields are so dynamic and full of uncertainty, the traditional methods of situation analysis deal with the uncertain, inconsistent and incomplete information in these contexts with limited capability. This paper proposes a novel approach for the distributed cooperative situation analysis based on the Dialectic Semantics of the Argumentation Theory. The approach analyzed and represented the claims of different participants, the attack relationships among the arguments from different participants, and the focuses of contradictions between different claims using the multilateral dialogue games, and constructed a Grid of Dialectical Analysis Trees to assist the decision makers to cooperatively solve the inconsistencies of their beliefs and the conflicts among their standpoints in situation analyses. This study will provide a new methodology for the situation analysis of Joint Operations.