Embodiments of this application provide a method and an apparatus for determining virtual machine VM migration. The method includes: after a VM is migrated, sending a gratuitous ARP packet or a RARP packet to an in-migration VTEP device; obtaining, by the VTEP device, a MAC address of the VM, searching an ARP cache table based on the MAC address, and obtaining an IP address of the VM; and constructing an ARP unicast request packet by using the IP address as a destination IP address, and if the VTEP device receives an ARP response packet sent by the VM for the ARP unicast request packet, determining that the VM is migrated. In the method provided in an embodiment of this application, after the VM is migrated, an in-migration device of the VM needs to obtain only the MAC address of the VM, and can determine that the VM is migrated. The in-migration device does not need to be limited by a case in which the virtual machine sends the gratuitous ARP packet, to perceive in-migration of the VM. This effectively improves compatibility of a virtual machine configuration.