Disclosed is a packet processing method and system, and a device. A status value used to identify a topology status of service nodes at a specified time is preconfigured for a packet in a packet flow, so that when a service node in a next hop is selected for the packet, selection is performed not based on a topology status of current actual service nodes in the next hop, but based on the topology status, which is identified by the status value, of the service nodes at the specified time. As long as status values carried in packets in a same packet flow are the same, even if a topology status of service nodes changes, a same service node can still be selected for the packets in the same packet flow, thereby avoiding a problem of diversion of the packets in the same packet flow.