Abstract: To overcome the limitations of existing Discontinuous Deformation Analysis (DDA) in modelling the nonlinear softening behavior of rocks, this study proposes a modified DDA that incorporates an exponential softening failure model within a bond-enhanced DDA framework. Five benchmark problems are conducted to validate the accuracy of the modified DDA, including a two-block system, a three-point bending beam, a double-notched plate, a uniaxial compression test, and a Brazilian disc test. The numerical results indicate that block size significantly influences the simulated peak force and post-peak response, and that computational results gradually converge toward the experimental data as the block size is reduced. The pre-peak mechanical response, however, is not affected by block size. Furthermore, the modified DDA accurately simulates the mechanical responses of rocks under various boundary conditions, including crack initiation, crack propagation, stress-strain relationships and stress evolution. This study provides a robust numerical tool for predicting rock strength and failure behavior.