A Round-Robin Timing Exchange (RRTE) protocol is proposed for the distributed synchronization of wireless sensor network. Compared to the Timing-sync Protocol for Sensor Network (TPSN) and the Pairwise Broadcasting Synchronization (PBS) scheme, the power consumption for each sensor node (SN) of RRTE is much smaller than that of TPSN and is evenly distributed among each SN in contrast to the PBS method. In addition, the synchronization accuracy of RRTE falls within that of TPSN and PBS, and can be adjusted by controlling the number of SNs in one cycle of synchronization. This makes the synchronization protocol particularly useful for small-scale wireless sensor networks. Furthermore, to improve the accuracy of synchronization, a recursive second-order regression method is also proposed to smooth the timing adjustment of each synchronization step without requiring complicated computations.