Abstract: 802.1x authentication was usually distributed deployment. However, With the expansion of the campus network and increasement of the number of control devices, the management of equipment and authentication system become so inconvenience. On the other hand, centralized 802.1x could not locate the terminal. The problem of terminal location under centralized 802.1x was solved by using （NAS IP, Port, Vlan）three tuple, Super Vlan and dynamic address allocation technology. Centralized 802.1x authentication system was tested in the of Huazhong Science and Technology University campus network, and achieved good results.