This present paper describes the process and methods of the numerical analysis, including yielding criterion, 3-D geometrical model, rock mass mechanical parameters, initial geostress field, method to simulate excavation process, simulation method for supporting structures. Then, the paper gives the computational results of rock deformation and stability for the large cavern group and comparisons for three cases: with no supporting structures; with bolts and shotcrete lining but no prestress-cables and with all the supporting structures of bolts, cables and lining. Finally, the paper reaches several conclusions.