Abstract: This paper deals with numerical techniques and analysis for three dimensional seepage flow through foundation of a large pumping station and its adjoining earth dam. The purpose of this work is to solve more complex engineering problem by using finite element method. It states how to compute the complex situation with both the confined and unconfined seepage flow and recommends the interpolation method to find the position of intersecting line where the free surface meets horizontal drainage system. The free surface of seepage has been regulated automatically by computer program.