Abstract: In order to decrease the delivery latency, increase the throughput and lower the traffic loads, this paper presents MDD-MAC (multi-divided deliver MAC), a new synchronous MAC protocol with low delivery latency and low traffic loads. MDD-MAC minimizes collisions and overhearing by dividing data transmission cycle into two time slots, i.e. data sending slot and data receiving slot. To achieve low latency and energy-efficiency, MDD-MAC introduces an efficient group deliver mechanism by combining the topology information of network. We evaluate MDD-MAC on OMNet++ and compare it with DW-MAC and TMAC, two previous energy-efficient MAC protocols, under the scenarios of cross network, random networks and grid networks. In all experiments, MDD-MAC significantly outperforms those other protocols. For example, on scenarios of cross network with 43 nodes, the delivery latency and maximum buffer load for MDD-MAC is 67.59% and 89.16% less than that of DW-MAC, and 72.49% and 89.80% less than that of TMAC respectively. Specially, the average collision times for DW-MAC and TMAC is 8 and 34 respectively while the MDD-MAC is almost zero.