Abstract: The particle breakage has a significant effect on the stress-strain behavior of granular materials. An improved approach for modelling the particle breakage is proposed based on the discrete element method (DEM). This approach first simplifies the complicated stress condition into the maximum tensile one. A particle is allowed to break if the maximum tensile stress acting on it exceeds its tensile strength. The radius of the fractured particle is reduced. When the accumulated loss in mass reaches the critical value, new particles are inserted into the sample. The newly generated particles satisfy a fractal condition. In order to take the variability and size effect in particle strength into consideration, the tensile strengths of the uncrushed particles, the crushed particles and the newly generated particles all satisfy the Weibull distribution. This approach also obeys the mass conservation and can be implemented into the classical open-source package, which allows parallel computation in a multi-processor system. The validity of this approach is demonstrated by comparing the DEM simulation results of one-dimensional compression and direct shear tests with the data from the laboratory tests.