An Ethernet multicast method and device are provided, which relate to the communications technology field, and improve the capability of distributing multicast data in the Ethernet. The method includes: receiving a request from a host/multicast source, wherein the request carries a multicast Media Access Control (MAC) address of a destination multicast group; selecting, according to the request, a switch satisfying a particular optimization condition as a multicast root node corresponding to the multicast MAC address of the destination multicast group when it is determined that the multicast MAC address of the destination multicast group does not have the corresponding multicast root node; transmitting an identification of the multicast root node to the host/multicast source. The embodiments of the present invention are mainly applied to the process of the multicast data distribution in the Ethernet.