The distribution of the evolution network with growth supply chain

The evolution network of growth supply chain network has not only the characteristic of the scale-free network model, but also has a feature which a new node attach with an old node of the smaller degree based on the path preferential attachment. Over time increasing the scale of the network is growth. The degree distribution that informs the topology of the network is calculated with master equation method. The result has the power law exponent floating around 2.5. It is obtained by computer simulation. The image of distribution and the degree value has been the tail suddenly directing upward. When the time is long and the network is also a great scale, it is indicated that newly added nodes are connected nodes with larger degree value and that the role of the path preferential attachment is a small merit. This precisely reflects the level group of this network is higher than level group of the scale-free network. It is in good agreement with reality.