Abstract: The effect of the particle shape on the biaxial tests is simulated by the particle flow code in two dimensions (PFC2D). Through the analysis of four specimens with different particle shapes, it is shown that the particle shapes have great influence on the macroscopic property of the specimens with the same microscopic parameters and that three non-circular particles greatly improve the shear strength of the specimens because of their special particle shapes. And it is also shown that the variation of the macroscopic property of four specimens with the microscopic parameters is relatively close.