Aiming to decrease the energy consumption of MAC address in wireless sensor networks, we propose a new MAC address multiplexing compression algorithm. In our proposed algorithm, nodes' addresses are multiplexed using regional grid segmentation, which on a regional basis. An asymmetry MAC address allocation principle allocation using bit flag is also presented, which can weaken the negative effects for irregular distribution of sensor nodes. Theoretic analysis and experimental result shows that our algorithm plays a good performance in the situation that the wireless sensor networks are intensively deployed and the distributions of nodes are irregular.