A bit index explicit replication (BIER) packet sending method includes receiving, by a first node in a first BIER domain, a packet from a second node in a second BIER domain, where the packet carries an identifier of the second BIER domain, determining a BIER packet sending policy corresponding to the identifier of the second BIER domain based on the identifier of the second BIER domain and according to a preconfigured BIER packet sending policy, and encapsulating and sending a BIER packet according to the BIER packet sending policy.