Method for controlling access to multiple networks, communication system and related devices

A method of controlling access to multiple networks, comprising: receiving (101, 213, 311, 408, 509) by a user equipment, UE, information indicating multiple access sent by an access node, wherein the indication information multiple access is information on multiple access capability of a gateway data or information indicating that a data gateway supports multi-access function or information indicating that a data gateway does not support the access function multiple; determining (102) by the UE, depending on the indication information multiple access, if the UE uses a multi-access function; and initiating (103), by the UE, an establishment of connectivity access from multiple networks if the multi-access function is used.