The invention provides a seepage monitoring system applied to a geomembrane. The seepage monitoring system comprises a power supply unit, a plurality of monitoring sensing electrodes, a data collection unit and a control analysis unit, wherein the power supply unit comprises two power supply electrodes, the two power supply electrodes are prepared from nonmetal conducting materials and are respectively connected to the upper and lower parts of a main anti-seepage geomembrane; the monitoring sensing electrodes are prepared from the nonmetal conducting materials, are uniformly arrayed at the lower part of the main anti-seepage geomembrane and are used for collecting potential of a corresponding position of the lower part of the main anti-seepage geomembrane; the data collection unit is used for collecting potential data of each monitoring sensing electrode; and the control analysis unit is used for analyzing the potential data, collected by the data collection unit, of each monitoring sensing electrode, determining a potential abnormity region at the lower part of the main anti-seepage geomembrane, determining seepage points of the main anti-seepage geomembrane, and giving an alert. By collecting the potential data of each monitoring sensing electrode, the potential abnormity region at the lower part of the main anti-seepage geomembrane can be determined, and furthermore, the specific seepage points of the main anti-seepage geomembrane can be determined, and an alert is given, so that the problems that a metal electrode cannot resist acid, alkali and electrochemical corrosion are solved.