This paper proposes EL-MAC, a contention-based medium access control (MAC) protocol, which is efficient and low-latency for the wireless sensor network (WSN). EL-MAC introduces duty-cycle and virtual cluster scheme within the framework of S-MAC to reduce energy consumption and to self-organize network. Besides, Inspired by D-MAC, the scheme of data forwarding chain (DFC) is proposed for reducing the latency in multi-hop transmission. The experiment of simulation shows that EL-MAC has lower latency and higher throughput with comparative energy consumption on different traffic load condition than S-MAC.