Abstract: In order to deeply study the development of the conducting-water structure of working face floor with the mining process, and to prevent the occurrence of water accident, a real-time monitoring system of the apparent resistivity is developed. The system adopted low frequency AC perspective technology, pseudo-random multi-frequency signal synchronized transmitting technology, continuous high precision and full wave band data acquisition technology, and power frequency anti-interference technology, etc. By means of fiber-optic network in coal mine, the monitoring and warning system achieved underground unattended operation, ground remote control and real time data imaging. The application results showed that the system realized the real time remote monitoring of apparent resistivity under working face floor including goaf area.