Abstract: The seepage FEMcalculations and damslope stability analysis were conducted for Qingshan hydraulic project. The results reviewed that the thickness of the clay core-wall in damaffected the energy slope of seepage directly. Due to the clay core- wall in dam s in Qingshan hydraulic project are very thin, the seepage energy in core- wall fall rapidly, which may cause seepage damage in dam. The strong perviousness in the dambody and the foundation may cause abnormal seepage problem. Due to the effect of the seepage, the stableness on the downstreamdamslope can not be ensured. The computed results have provided the basis for the reinforcing the dams of Qingshan hydraulic project. It can be also a uesful reference material for analyzing the security of other hydraulic projects.