Abstract: There is medium Karst nature dolomite limestone at a mud storage site in Pingnan. Due to geological actions, the limestone has numerous crannies. The Karst in the dolomite limestone developed along the geology structure asymmetrically when the dolomite limestone influenced by the climate condition of high annual precipitation, high annual evaporation and high air temperature. And there are fourteen Karst areas at site. Karst is severer at shallow depth than at deep depth. The shallow Karst forms are sinkholes and Karst pits (Karst grooves). The main deep Karst form is Karst cranny. The Karst forms small underground river net and the underground water link with the underground water outside the site. The seepage at the site is pipe-seepage and cranny scatter seepage. There are strong, medium, and weak Karst seepage areas according to the seepage intensity. The method to deal with the seepage in the strong Karst seepage area is to silting the small Karst forms, step over the big Karst forms with boards, then carpet use clay and anti-seepage cloth. The method to deal with the seepage in the other Karst seepage areas are to silt the small Karst forms, chisel off the extrusive, then carpet use clay and anti-seepage cloth. 