The growth and evolution model of the knowledge network in agile supply chain is built based on the improved BA network model, aginst the features of dynamic growth and clustering of the knowledge in the agile supply chain. The node in the network is connected to others based on the relationship strength. Attributes of the knowledge subject in the network is defined and the diffusion process model of knowledge in the network is proposed on the basis of the growth and evolution model above. Finally, the average knowledge stock of the network and the difference coefficient of knowledge in the network are comparative analyzed by using the method of computer simulation, when the knowledge subject in the network chooses different mechanism of preferential attachment, so that the effective countermeasures are obtained to improve the efficiency of knowledge diffusion.