A multicast packet transmission method and an apparatus are provided that relate to the communications field and define how multicast data is sent to stations (STAs) by using a multicast association identifier (AID). The method includes: allocating, by an access point (AP), a corresponding multicast AID to STAs, where the multicast AID is set in a short media access control (MAC) header of a multicast packet; and sending, by the AP, the multicast packet to at least two STAs, so that the at least two STAs determine, according to the multicast AID, whether the multicast packet is a multicast packet corresponding to the at least two STAs, where the at least two STAs are in a same multicast group.