Abstract. After the impoundment of the reservoir, in the role of the water head, there will be seepage in the dam, which will produce the seepage of the dam, the dam cross section and intersection called saturation line. Saturation line is the lifeline of the safety of tailings dam, saturation line height is directly related to the dam stability and safety properties, when the saturation line depth is 0m, this will produce piping, which is the direct cause of the dam break Introduction. In water conservancy and hydropower, it is mainly to monitor the location and change of the line of the dam by calculating the height of the saturation line, determining the influence of the stability of the dam, in order to determine whether the dam is stable, to ensure the safe operation of the dam. Capacity, flow rate, precipitation can be intuitive monitoring of hydrological parameters Compared with above parameters monitoring saturation line is hidden, the monitoring and analysis is real-time and intuitive, automation and intelligent, so the system chooses mixed programming of MATLAB and VC + + to achieve saturation line monitoring.