Abstract: A cooperative mechanism amlong multiple agents was proposed. In the cooperative mechanism, a utility value was used to generate a preferred order for agents under different cooperative patterns. This utility value was achieved by computing the cooperative utility between one agent and the others under different tasks using a utility function. According to this mechanism, agents can automatically choose the cooperative pattern, which is the best to fit themselves to accomplish their missions. Meanwhile, driven by utility, group task income can achieve the optimum, which enhances the cooperation efficiency of agent groups. A prototype system was designed at last to validate the proposed cooperative mechanism. The effectiveness of this cooperative mechanism has been proved under the prototype system.