A method and a device for multicast packet processing are disclosed. The method includes: A first network device obtains a data packet; and the first network device generates a first multicast packet and a second multicast packet based on the data packet. The first multicast packet includes first iFIT information and a first multi-level flow identifier. The second multicast packet includes the first iFIT information and a second multi-level flow identifier. The first multi-level flow identifier and the second multi-level flow identifier are different, to identify different forwarding paths of the generated first multicast packet and second multicast packet respectively. In the method, in a point-to-multipoint multicast data flow transmission scenario, a plurality of multicast data flows can be identified, to perform iFIT detection on each of the plurality of data flows, so as to implement packet loss and delay detection, path restoration, and the like for the multicast data flows.