This application provides a packet sending method and a network device, where a first network device in a multichassis link aggregation group is coupled to a user-side device using a first port, and is coupled to a second network device in the multichassis link aggregation group using a second port. The first network device configures a first preset Address Resolution Protocol (ARP) entry for the user-side device when the first port and the second port have not become faulty, and when the first port becomes faulty, can directly forward a packet whose destination is the user-side device to the second network device using the second port and the first preset ARP entry. Then, the second network device forwards the packet to the user-side device.