Based on investigation and applications in precision agriculture, a self-designed moisture wireless sensor was presented in the paper, a wireless sensor network was established for monitoring moisture content and water height of field soil. The architecture of the wireless sensor network was constructed, and the smart irrigation control system was designed based on the network. The irrigation test was implemented by real-time moisture data and expert data. The system was proved to be applicable and feasible for applying in the rice growth process and to be a good exploration in the field of precision agriculture and sustainable water resources.