Abstract: The traditional Reference Broadcast Synchronization (RBS) algorithm has a problem that network overhead is very large as the network nodes increase in Wireless sensor networks. An Energy-efficient RBS (ERBS) scheme is presented to work out the network overhead issue. Firstly, every receiving node, which is required to receive a couple of reference messages, computes mean phase offset to its nonadjacent receiving nodes, and estimates phase offset by maximum posteriori estimation; Secondly, the algorithm uses least-squares linear regression to fit clock skew periodically. The analysis on simulation result indicates that ERBS algorithm improve synchronization precision and reduce energy usage over RBS.