Abstract：The stability of large-scale excavations always is a key problem in underground water power stations. In order to evaluate the stability of these excavations，the three-dimensional nonlinear finite element method is used usually. The basic ideas about how to use finite element method in stability analysis of underground excavations are introduced，including the choice of constitutive relation of rock mass，iterative method of nonlinear computation，failure criterion of surrounding rock，optimal ways of stability evaluation and simulation methods of anchorage supporting structure. To realize the visualization of results of computation，visualization software of underground excavations¢ finite element analysis is developed based on the object-oriented idea. This software can draw conveniently spatial contours and vector diagram of every physical quantity and display structure¢s deformation and the distribution condition of failure area. Besides，the software can also show anchorage structure including anchor rod and anchorage cable and its stress. At last，above calculation methods and visualization software are used in an engineering example. The results show that the calculation methods presented above are rational and effective；and the visualization software is powerful in evaluation of computation results.
