A method and an apparatus for joining a centralized cluster is disclosed. The method includes: receiving a DMG Beacon frame sent by a first S-AP, where the DMG Beacon frame includes cluster information of the first S-AP; measuring, according to the cluster information of the first S-AP, signal quality and a state of each Beacon SP included in a BI of the first S-AP; if a Beacon SP whose state is an idle state is obtained by means of measurement, associating the Beacon SP with the first S-AP as a non-PCP/non-AP station, and receiving an Announce frame sent by the first S-AP; selecting one S-AP from the first S-AP and the second S-AP as a to-be-joined S-AP; and joining a centralized cluster of the to-be-joined S-AP.