Abstract: Conflict is one of the most universal phenomena in our society. Conflict analysis and negotiation are of very importance in the field of the economy, politics and military, et al. In this paper, by means of integrating conflict analysis and the rough set theory, informatinn system is used to describe conflict problem and the concept of conflict matrix is put forward. In this way, based on the different definitions of conflict function and its threshold, methods of defining coalitions are presenied. For this model, strength - strategy analysis with threshold is given. And, the negotiation model based on the coalitions is put forward to reduce the degree of conflict. In addition, the different functions of reduct and conflict degree are clarified. The discernibility matrix Ⅱ and its description using conflict function are presented.