A Slow Protocol packet processing method includes receiving, by a network device, a first Slow Protocol packet, determining, based on port information of a port of the network device receiving the first Slow Protocol packet, that a negotiation process is already completed between the network device and the transmit end device, querying, based on device information of the transmit end device carried in the first Slow Protocol packet, whether a device information base stored by the network device in the negotiation process includes the device information of the transmit end device, and identifying the first Slow Protocol packet as a valid packet in response to a result that the device information base includes the device information of the transmit end device.