A network is composed of a set of nodes (vertices) and the set of arcs (edges) between nodes. There are quite a wide variety of systems which can be described as complex network that play important role in our life. Traditionally, when exploring a large system, people used to divide it into small parts, and then examine each part respectively. However, many proof have showed that the relation between parts is at least as import as the part itself. However, the structures of these systems are unknown which make the relation unobserved. The desire to understand the structure of these systems has step up the study of the modelling of complex network.