In view of the technical problems that exist during implementing IP address anti-spoofing in an access node device in an IPv6 access network, the present invention proposes a packet forwarding method and apparatus in an IPv6 Access Node, for forwarding a packet from a Residential Gateway. In the method, the access node device first receives a packet from the Residential Gateway, then obtains a network prefix in a source UPv6 address of the packet, judges whether the network prefix in the source IPv6 address of the packet is a valid network prefix of a CPN corresponding to the Residential Gateway, and if yes, forwards the packet finally. Particularly, in the present invention the access node device can automatically obtain valid network prefix using technical means such as snooping a network prefix allocation reply message. Therefore, the present invention greatly increases operation efficiency and security of the IPv6 access network and simplifies network management of the IPv6 access network.