Abstract: To study the relationship between the macro and micro parameters of the PFC2D model and calibrate the micro parameters, according to the mechanical characteristics of the material, the parallel bond model is used as the constitutive model of the particle contact. Based on the analysis of the influencing factors of the micro parameters, the macro parameter standard and specific process of the trial and error method to calibrate the micro parameters are proposed. In the microscopic parameter calibration of uniaxial compressed particle flow model for similar materials, the macroscopic parameters, stress-strain curves and failure characteristics of the specimens calculated by the numerical model with microscopic parameters are similar to the results of laboratory physical tests.