Abstract：Based on the conventional triaxial compression tests of the Three Gorges granite，the complete stress-strain curves under different confining pressures have been attained. The test results show that the peak and residual strengths increase，and plastic deformation of the Three Gorges granite can be improved with increasing the confining pressure. Based on the stress-strain curves of triaxial experiments，the softening law of physical property parameters is studied，and a post-peak softening numerical model is established by analyzing the relationship between the strength parameters of granite and parameters of post-peak strain softening with elasto-plastic theory and curve-fitting. Conclusion is drawn that cohesion decreases gradually and keeps almost unchangeable with the increasing of strain softening parameter in the strain-softening process of the Three Gorges granite. The post-peak softening model of granite is used in software FLAC3D to simulate the compression tests，and the numerical simulation based on the model approximately matches the triaxial experiments.
