The present invention relates to the field of communications technologies, and discloses a beam tracking method, apparatus, and system, so as to ensure rapid discovery and to switch from an optimal link to a backup link in time, or switch from a backup link to an optimal link, thereby effectively improving a throughput of a system link. The beam tracking method includes: transmitting, by a beam tracking initiator, a beam tracking request to a beam tracking responder; receiving, by the beam tracking initiator, an enhanced beam tracking training auxiliary sequence transmitted, according to the enhanced beam tracking request, by the beam tracking responder; and when it is determined according to a reception detection result of the enhanced beam tracking training auxiliary sequence that it is necessary to switch to a backup beam link, transmitting, by the beam tracking initiator, first link switching information to the beam tracking responder.