Proper soil moisture content is one of the necessary conditions for crop growth and steady yield. The soil moisture real time measurement is the basis of reasonable irrigation and an effective way for saving water resources. This paper presented a real-time monitoring system of volumetric soil moisture content. The system consisted of field data collection terminal and monitor center. The data is transmitted by wireless communication between the measurement field and monitor center. The soil moisture content is obtained by measuring the sensor frequency variation with the soil dielectric constant. With solar cell, solar energy was collected and stored in accumulator cell to provide power supply for field data collection terminal. The experimental result shows the system is operating good and working stably, it is promising to be used for real time measurement of soil moisture.