Abstract: In this paper, in-situ tests and laboratory tests through soil excavation of the deep overburden dam foundation demonstrated that with the cover layer deposition time older, the greater depth and under covering overburden, deep overburden's anti permeability performance and machnical property is improved obviously. In order to make full use of the covering layer under the dam foundation, save construction period and reduce the manufacture cost, we have summarized domestic and international experiences about the overburden utilization. The principle of overburden utilization is put forward.At the same time, This study can promote the technical development of dam in deep overburden layer, can provide reference for water conservancy and hydropower engineering technical personnel