With the rapid development of wireless sensor network, the networks become more complex. Original synchronicity algorithms may not work efficiently for complex mesh network. In this paper, we present a new firefly-inspired stochastic coupled synchronicity strategy with simplified discrete phase model in wireless sensor network. It is a software-based strategy, which can more fully utilize the communication bandwidth and be insensitive to packet loss rate. First, this paper presents a simplified discrete phase model and the synchronicity strategy for details. The stability of this strategy is evaluated and the effects of varying parameters in the strategy are found out via analyzing simulation results. Furthermore, the experimental verification is implemented on JN5148 hardware platforms. Thus we demonstrate that our strategy can be used in time synchronicity effectively for distributed systems.