Abstract: Through considering the uncertainty of alliance profit and the expectation of each member in alliances to profit, a game model based on prior consultation for profit distributing of a dynamic alliance was set up. By analyzing the function of a prior contract of profit distributing in the cooperation behaviour and result of members, the effects of different distributing mechanisms on the total profit of a dynamic alliance were discussed, and the basic principle of determining the profit distributing mechanism of a dynamic alliance based on prior consultation was proposed. The research result shows that all the members in a dynamic alliance will select their behaviours in light of the prior contract of profit distributing to maximize their profit and so have an effect on the result of cooperation.