An enhanced block acknowledgement (BlockACK) method for the aggregate MAC protocol data unit (A-MPDU) transmission is proposed. In the proposed method, the position information of each aggregated subframe is carried by the A-MPDU using the reserved bits and a novel position information control is used to acknowledge the A-MPDU. By utilising the enhanced BlockACK method, the aggregation level of the A-MPDU transmission will not be constrained by the effect of lost subframes. Theoretical analysis and simulation results demonstrate that the enhanced BlockACK method can achieve a more stable aggregation level and higher throughput than the conventional one.