This application provides a load sharing method. The method includes: establishing a first tunnel and a second tunnel between a first network device and a second network device, where the first tunnel and the second tunnel form a bonding tunnel through hybrid bonding; sending, by the first network device, a plurality of data packets to the second network device; determining, by the first network device, a usage status of buffer space of a bonding tunnel reorder buffer of the second network device based on an acknowledgment response returned by the second network device; and performing, based on the usage status and according to a specified load sharing policy, load sharing between the first tunnel and the second tunnel for a packet to be transmitted by the first network device to the second network device. According to the method in this application, transmission efficiency of the bonding tunnel is effectively improved.