An access method of network terminals, an access system and gateway are provided. In the access method of the present invention, providing an access proxy to the service network system for a network terminal initiating an access request but not configured with the subscriber certification information to the service network system by the use of subscriber certification information to a service network system configured on a network terminal. The access system of the present invention includes a digital gateway configured with a gateway multimedia service processing module. By sharing the subscriber certification information to the service network system configured on the network terminal connected to the digital gateway, the network terminal not configured with the subscriber certification information to the service network system can realize the access certification to the service network system.