Abstract: Agent organization can be used for multi agent problem solving so as to potentially decrease the difficulty of problem solving and complexity of interaction. Among many problems, the agent organization formation and evolution are the key problems to agent based computing and cooperation. In this paper, a structure oriented mechanism of organizational formation and evolution is presented, which solves problems of blindness and inflexibility, ensures the utility rationality and personal preference of agents, describes the satisfied properties of organizational evolution, and improves the methods of organizational formation and evolution presented by Shehory, Kraus, Glaser et al .