An association establishment method and apparatus, for carrying out the method are described. The association establishment method includes



broadcasting, by an access point (AP), a trigger frame, wherein the trigger frame is used to trigger one or more unassociated stations STAs to perform uplink data transmission and indicate one or more available subchannels for random accessing of the unassociated STAs. The method further includes receiving, by the AP, one or more association request messages sent on available subchannels acquired by the unassociated STAs. Thereafter, the AP broadcasts a multi-block acknowledgement M-BA frame, wherein the M-BA frame includes one or more pieces of association acknowledgement information and the association acknowledgement information is acknowledgement information of the association request message.