Abstract: In the group conflict, the biggest contradiction often is to fight for the ownership of interest, and the focus is on how to make the interest maximization. When the two parties in the game can’t properly resolve the contradiction and the game is stalemated, we introduce the third party non-governmental organizations to mediate contradiction and even resolve the contradiction between the two parties. Through analysis of the game behavior between main stakeholders in group conflict, this paper uses the evolutionary game method to establish the tripartite game model with the non-governmental organizations and the two parties in conflict, and pursuits equilibrium points of the game. Through the analysis of the equilibrium, the paper concludes whether the two parties choose mediation depends on the non-governmental organizations’ probability of success to mediation, the costs of mediation, and the loss generated by that conflict in which the two parties don’t compromise