This paper studies the relationship between the organizations and their environment firstly. On account that the organizations try to meet needs of customers and gain competitive advantage, the complexity of organization and their environment is increasing simultaneously nowadays. As result, the survival of an organization depends on its ability to create a higher degree of complexity than its environment. This will lead to the bewilderment for managers to increase or decrease the complexity of the organizations. The key point to solve this dilemma is to find the equilibrium of complexity between the organizations and their environment.