A network device sends multicast configuration information to a terminal device, where the multicast configuration information corresponds to a first multicast service, the multicast configuration information includes first indication information, and the first indication information indicates that the terminal device sends first feedback information for the first multicast service. The terminal device receives the first multicast service based on the first multicast configuration information, and then sends the first feedback information corresponding to the first multicast service to the network device based on the first indication information in the first multicast configuration information. The feedback mechanism applies to a multicast transmission technology and improves transmission reliability of a multicast service.