Abstract: In order to achieve the security communication and scalability of large-scale enterprise network, a cross-regional enterprise network based on multi-policy configuration is designed. According to the function of networks, autonomous domains and network addresses were divided. Virtual local area network trunk protocol, port on the second layer and other policies were assigned on the switching layer. Correlated routing protocols were used for communicating among autonomous domains on the routing layer. Border gateway protocol was deployed to establish a peering relationship and manage remote sites respectively. The secure shell protocol was used to realize the remote access function of enterprise network and the Internet access at the same time. A variety of encryption authentication technologies were applied to improve the coefficient of security. Enterprise networks were operating on Web-IOU V22 UD simulation platform to prove the reasonable routing decision and security of communication for enterprise network.