Method and system for fusing WLAN access gateway, mobile network and wireless broadband network

The invention provides a method and a system for fusing a WLAN access gateway, a mobile network and a wireless broadband network, relating to the field of communication. In one method for fusing the mobile network and the wireless broadband network, the WLAN access gateway receives a registration request of accessing to the wireless broadband network, which is sent by user equipment, wherein the registration request comprises a user identification code of a user identification card inserted in the user equipment and X_CT_Tunnel information; the WLAN access gateway returns a random number to the user equipment; the user equipment carries out access authentication according to the random number based on the user identification card to generate an authentication code; the user equipment sends the authentication code and the random number to the WLAN access gateway; the WLAN access gateway completes access authentication of the user equipment with an authentication server in the mobile network according to the authentication code and the information of the registration request; and the WLAN access gateway responds to the registration request of the user equipment according to an authentication result. The invention realizes network fusing of the mobile network and the broadband internet based on the WLAN access gateway.