An AID allocation method for a multi-link device, includes: An access point multi-link device generates and sends a first frame. Correspondingly, a station device receives and parses the first frame to obtain an AID that is allocated to the station device and carried in the first frame. The AID is neither a BSSID that can be supported by a first-type access point in the access point multi-link device nor an identifier of an access point in the access point multi-link device. The first-type access point is an access point for establishing a link between the station device and the access point multi-link device.