An information transmission method and system, and a convergence gateway, where the method includes receiving, by the convergence gateway, a service request from first user equipment, where the service request includes identity information of the first user equipment and service information of the first user equipment, obtaining, by the convergence gateway, first user permission information of the first user equipment in a first network according to the identity information of the first user equipment, and determining, by the convergence gateway based on the first user permission information, a forwarding manner for forwarding the service information to second user equipment. A convergence service for a private network and a public network is implemented using the convergence gateway such that indoor communication signal quality can be improved, and network construction costs can be reduced.