A method and a system for notifying access network location information are provided. The method includes that in a PMIPv6 architecture, a Mobile Access Gateway (MAG) sends a circuit ID to a Local Mobility Anchor (LMA) by carrying the circuit ID in a proxy binding update message; and in a GTP architecture, a local GTP peer sends a circuit ID to a correspondent GTP peer by carrying the circuit ID in a Create Session Request message, a Modify Bearer Request message or a Delete Session Request message. In the disclosure, an MAG can notify an LMA of access network location information of a UE in a PMIPv6 architecture, and a GTP peer can notify a correspondent GTP peer of access network location information of a UE in a GTP architecture.