Based on RBV, this paper suggests a new definition of the nature of the industrial cluster. The author proposes that the industrial cluster is the entity of resource agglomeration that consists several relative enterprises and organizations, which are located at a special geographic region. The nature of cluster's competitive advantage is to achieve the maximum of the cluster's synergistic effect by clustering and association, namely the process of increasing return, which originates from the cluster's capabilities of division and cooperation and sharing of knowledge (technology) based on resource agglomeration.