Abstract: This paper states the principle and method to solve three-dimensional steady seepage flow field with free surface by finite element method and utilizes the characteristics of finite element, method to find out the methods of regulating the free surface&seepage surface and calculating seepage discharge through water section of any form in homogeneous and heterogeneous earth dams. It also states some techniques of three-dimensional steady seepage flow problem within finite region that being carried out on TQ-16 electronic computer.Finally, by analyzing the homogeneous and heterogeneous seepage flow field associated with engineering practical examples and that in camparison with field data it is verified available. Thus the experience to compute three-dimensional seepage problem by widely applying electronic computer is presented.