Abstract: A tailings reservoir is located in the karst area , and the tailings leakage in the downstream of the rainy season causes local water and soil pollution. After field investigation and preliminary analysis of the hydrogeological conditions in the reservoir area, it is believed that the main cause of tailings leakage is karst collapse in the reservoir area connecting to karst pipelines. Using a comprehensive geophysical prospecting method combining EH4 continuous conductivity profiler and five-pole electrical sounding, EH4 detection is carried out firstly, and then five-pole electrical sounding is conducted at the abnormal location delineated by EH4. It is found that a northeast trending fault and its secondary fault structure are developed in the middle of the karst depression in the reservoir area, and there are large number of low-resistance areas within 80 m below the surface along the structure, which are presumed to be main water channels. Using the ground curtain grouting method, the main karst channels of tailings leakage are identified by drilling. The aggregate input is determined by theoretical formula calculation, and the dynamic water grouting technology of adding aggregate firstly, then injecting double slurry and then injecting cement single slurry is used to effectively block large karst caves or karst pipelines. Other karst and fault structures are grouted and blocked by ordinary grouting technology. After the curtain grouting treatment, there is no collapse in the reservoir area and no tailings leakage in the downstream. The practice shows that the comprehensive geophysical prospecting technology and the ground curtain grouting method can effectively solve the problem of the exploration and control of the tailings leakage channels, and can provide a reference for similar tailings leakage control in the future.