The utility model discloses a carry on anti - seepage prevention of dam foundation system of straining structure of double -deck level in deep overburden high dam belongs to the design of hydraulic and hydroelectric engineering building and builds technical field. The utility model provides a build fastly, rare clay quantity obviously reduces, the obvious carry on anti - seepage prevention of dam foundation system of straining structure of double -deck level in deep overburden high dam who reduces of construction cost. The seepage prevention of dam foundation system including the excavation foundation ditch, arrange the clay core in the dam body and arrange the concrete cut -pff wall in deep overburden, the seepage prevention of dam foundation system still include foundation ditch rockfill material backfill layer, foundation ditch rockfill material backfill layer arrange the excavation foundation ditch in, clay core arrange foundation ditch rockfill material backfill layer's top, the concrete cut -pff wall upwards pass along vertical foundation ditch rockfill material backfill layer after imbed clay core in.