Embodiments of the present invention provide a method and an apparatus for implementing a multicast service. The method includes: constructing a multicast service notification packet, and sending the multicast service notification packet to a user terminal; the multicast service notification packet may be a return notification packet for responding a request of a user for joining a multicast group or an abnormity notification packet for notifying a user of reason for an abnormity in the multicast service or the reason that the user fails to join the multicast group. Therefore, it is effective to improve the user's satisfaction of a multicast video service provided by an operator and to improve the operability and the manageability of a multicast video network.