A multi-link aggregation transmission method and a related apparatus. The method includes: a receive end receives at least one of a data frame and a BAR frame over a plurality of links between the receive end and a transmit end, where the plurality of links includes a first link. The receive end receives a block acknowledgment request BAR frame over the first link, where the BAR frame carries SSN_1 corresponding to the first link. The receive end adjusts, based on SSNs corresponding to all the links, a value of a current starting sequence number WinStart of a scoreboard window. The receive end processes, based on the adjusted WinStart, a data frame received over the plurality of links. The receive end can adaptively adjust the WinStart.