In the data transmission method, a MAC layer receives data from an upper layer, classifies the data according to destination addresses and traffic identifiers, aggregates the data by destination address and traffic identifier as a first transmission unit, aggregates the first transmission units having the identical destination address as a second transmission unit, and transmits the second transmission units having different destination addresses in a single frame. The data transmission method allows packets transferred from the upper layer to be hierarchically aggregated by DAs and TIDs and then packaged into a data unit for each destination such that it is possible to transmit the data at an optimal data rate for each destination terminal.