Flexible form can effectively balance the contradiction between change and preservation in evolutive processes of firms. Organizational structure can be divided into rigid form, planned form, flexible form and chaotic form. Each of them is the typology form coping with change and preservation in certain condition. The forms can be developing with the change of environment. The trajectory is divided into the natural trajectory of routinization and the reverse trajectory of revitalization, and is explained by theories of Managerial Entropy and Managerial Dissipative Structure effectively.