The invention belongs to the access authentication technology field of mobile terminal of wireless band networks, which is characterized in that: for the mobile terminal of dynamic host configuration protocol DHCP which has already completed standard, the access authority of the network IP address and MAC address thereof have already been respectively authenticated by the access authentication gateway beforehand, and the MAC address is confirmed by the DHCP server, only needs to well plan the IP address connected with the mobile terminal by the network management personnel, and respectively notice the access authentication gateway and DHCP server, then, DHCP server distributes an IP address which accesses to the IP address segment of mobile terminal to the mobile terminal which belongs to the MAC address list beforehand, thus, only needs the mobile terminal to put forward application of request message of accessing to the network to the DHCP server, and can access to the network after checking the MAC address thereof by the DHCP server. The invention balances the load between access authentication gateway and DHCP server, and has wide applicability and convenience.