A method and system for notifying information applied to an Evolved Packet System/General Packet Radio Service network implemented by a Software Defined Network is provided, in which, a controller reselects a gateway to obtain a new gateway and sends user plane information of the new gateway to a front-end network element. The user plane information comprises user plane address information of the new gateway. The controller sends a GPRS Tunnel Protocol (GTP) notification message or GTP Update Bearer Request message carrying the user plane information of the new gateway to the front-end network element; or sends a GTP Update Bearer Request message carrying an update indication to the front-end network element, sends a bearer response message carrying the user plane information to the front-end network element through a GTP Modify Bearer Response after receiving a GTP Modify Bearer Request message sent by the front-end network element.