A load balancing method, wherein the method comprises: obtaining, by a first network device, a first Internet Protocol IP packet, wherein the first IP packet comprises first load balancing information, the first load balancing information indicates the first network device to send the first IP packet in a load balancing manner, the first load balancing information comprises first application characteristic information, and the first application characteristic information describes a characteristic of a first application associated with the first IP packet; determining, by the first network device, a first link based on a hash algorithm and the first load balancing information, wherein the first network device communicates with a second network device over a plurality of links, and the plurality of links comprise the first link; and sending, by the first network device, the first IP packet to the second network device over the first link, wherein the first network device and the second network device are forwarding devices configured to transmit data flows between terminal devices and a server, to implement load balancing; characterized in that the first application characteristic information comprises application identifier information of the first application, and the application identifier information of the first application identifies the first application, wherein the first IP packet is a first IP version 6 IPv6 packet comprising a segment routing header SRH, and the sending, by the first network device, the first IPv6 packet to the second network device over the first link comprises: encapsulating, by the first network device, an IPv6 basic header at an outer layer of the SRH of the first IPv6 packet to obtain a second IPv6 packet, wherein the IPv6 basic header carries second application characteristic information, and the second application characteristic information is information obtained by hashing the first load balancing information based on the hash algorithm; and sending, by the first network device, the second IPv6 packet to the second network device over the first link. obtaining, by a first network device, a first Internet Protocol IP packet, wherein the first IP packet comprises first load balancing information, the first load balancing information indicates the first network device to send the first IP packet in a load balancing manner, the first load balancing information comprises first application characteristic information, and the first application characteristic information describes a characteristic of a first application associated with the first IP packet; determining, by the first network device, a first link based on a hash algorithm and the first load balancing information, wherein the first network device communicates with a second network device over a plurality of links, and the plurality of links comprise the first link; and sending, by the first network device, the first IP packet to the second network device over the first link, wherein the first network device and the second network device are forwarding devices configured to transmit data flows between terminal devices and a server, to implement load balancing; characterized in that the first application characteristic information comprises application identifier information of the first application, and the application identifier information of the first application identifies the first application, wherein the first IP packet is a first IP version 6 IPv6 packet comprising a segment routing header SRH, and the sending, by the first network device, the first IPv6 packet to the second network device over the first link comprises: encapsulating, by the first network device, an IPv6 basic header at an outer layer of the SRH of the first IPv6 packet to obtain a second IPv6 packet, wherein the IPv6 basic header carries second application characteristic information, and the second application characteristic information is information obtained by hashing the first load balancing information based on the hash algorithm; and sending, by the first network device, the second IPv6 packet to the second network device over the first link. encapsulating, by the first network device, an IPv6 basic header at an outer layer of the SRH of the first IPv6 packet to obtain a second IPv6 packet, wherein the IPv6 basic header carries second application characteristic information, and the second application characteristic information is information obtained by hashing the first load balancing information based on the hash algorithm; and sending, by the first network device, the second IPv6 packet to the second network device over the first link.