The invention relates to a network safe simulation system and relative imitation method. The logical function of said network safe simulation system comprises: a virtual network module, a attack-defend dynamic chain connection base, a system control module, and a display module, while said logical functions are displayed by the control layer, virtual network device layer, public interface layer, middle layer and bottom function base. The virtual network device can simulate the host machine, router, firewall, network card, concentrator, and network wire on the single machine to connect each virtual network device to form the virtual network. The process that using said virtual network to process the safe simulation comprises: first, setting the user program; distributing system parameter document; coding the system; imitated operating the coded system in the operating system; at last collecting the simulated data according to which makes the network safety analyst. The invention has easy operation and extended availability, which can be used as network safety research simulation environment and imitation platform.