The paper analyzes the characteristics of evolution of cluster’s size form the view of interdependencies between firms’actions. The results indicate that with the decrease of independencies between firms’actions, the size of cluster presents the expanding trend and the shakeouts in the number of firms are less remarkable, even no shakeout. In addition, the survival rates of firms are lower and new entrants take an import action on the improvement of cluster’s efficiency when independencies between firms’ actions are higher, but when they are lower, the survival rates of firms are higher and the entry barriers are lower.