The technique, method and its application of a geomechanical model used for studying the entire stability problem of high arch dam are discussed. In geomechanical model on material simulation, except that rock deformation parameters of rock must be simulated, discontinuous surfaces in dam or rock mass, such as cracks, faults, soft interlayers, the distribution of obvious connecting joints and fissures, and non-linear characteristics of rock in dam base, must be simulated. It does not only provide a state under a given load, but also gives a visual view and quantitative results by studying a changing process from deformation to destruction under gradually increasing load. Jingping Dam is the highest hyperbolic and thin arch dam among constructing arch dams in the world. Since huge water pressure and complex geology condition, the design and analyses to the dam are out of current codes. So the stability safety of Jingping Dam is a remarkable problem. That geomechanical model is applied to estimate and validate entire stability of Jingping High Arch Dam has a very important signification.