A packet processing method, node, and system. An ingress delivery node receives a notification message that is returned by an egress delivery node after the egress delivery node receives a first packet, where the notification message includes modification information carried in the first packet, modifies, according to the modification information, a subsequently received second packet that belongs to a same service flow as the first packet, and sends the modified second packet to the egress delivery node. After modifying the subsequently received second packet that belongs to the same service flow as the first packet, the ingress delivery node directly sends the subsequently received second packet to the egress delivery node such that the second packet does not need to be processed by a service chain between the ingress delivery node and the egress delivery node.