In the field of network communications, a protection method for a multi-domain network includes: after a second node detects that a first link fails, disconnecting a first protection path on the node, connecting a first sub-path and a path that is within a second domain, uses the second node as an endpoint, and is used to bear a service; sending, on the first sub-path, a first failure monitoring message that carries first maintenance information to a third node, where the first maintenance information is the same as second maintenance information carried in a second failure monitoring message; the second failure monitoring message is a message that is sent on the first protection path by a first node to the third node and is used to monitor a failure of the first protection path.