A wireless sensor network (WSN) node is designed for monitoring of rural water supply plant in order to solve the problems of wireless communication barrier, postponed pollution warning and high cost, etc. The node uses a STM32F103ZET6 as a processing core, a WLK01L39 RF chip with peripheral circuits as wireless communication module, and a sensor module consisting of a mutifuctional sensor from American ASI for dissolved oxygen , pH, and temperature, and a WQ730 turbidity sensor from Global Water. The communication protocol, time synchronization algorithm and application program are designed for the node. A sleeping and waking up work mode is applied to reduce power consumption. The communication distance and power consumption of the node were tested and analyzed. The results showed that the node works stably and trustfully. The available communication distance is up to 500 m in the open areaThe average working current is lower than 50 mA as well as a sleeping current lower than 25 μA.