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. 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.